WO1999055805A1

WO1999055805A1 - Method for marking liquids with at least two marker substances and method for detecting them

Info

Publication number: WO1999055805A1
Application number: PCT/EP1999/002452
Authority: WO
Inventors: Frank Meyer; Gerhard Wagenblast; Karin Heidrun Beck; Christos Vamvakaris
Original assignee: Basf Aktiengesellschaft
Priority date: 1998-04-23
Filing date: 1999-04-12
Publication date: 1999-11-04
Also published as: DE19818177A1; AU3707399A; AR016218A1; TW460571B; PE20000464A1

Abstract

The invention relates to a method for marking liquids with at least two marker substances, characterised in that said marker substances are absorbent in the spectral range of 600 to 1200 nm and emit fluorescence radiation as a result, in that their absorption ranges are essentially non-overlapping and in at least one of the marker substances has a wavelength of more than 850 nm at its absorption maximum. The invention also relates to a method for detecting marker substances of this type in liquids. This method is characterised in that the source of radiation used emits radiation in the absorption ranges of the marker substances so that the fluorescence radiation emitted by said marker substances is then detected, or in that an appropriate source of radiation is used for each individual marker substance, said source of radiation emitting radiation in the absorption range of the marker substance and the fluorescence radiation emitted by said marker substance being detected. The invention also relates to liquids marked according to the inventive method.

Description

Process for marking liquids with at least two markers and process for their detection

description

The present invention relates to a method for marking liquids with at least two marking substances, which is characterized in that the marking substances absorb in the spectral range from 600 to 1200 nm and as a result emit fluorescent radiation, have essentially non-overlapping absorption regions and at least one of the markers has a maximum absorption wavelength of more than 850 nm.

The present invention further relates to a method for the detection of such markers in liquids, which is characterized in that a radiation source is used which emits radiation in the absorption regions of the markers, and the fluorescent radiation emitted by the markers is detected or which is characterized in that a corresponding radiation source is used for each individual marking substance, which emits radiation in the absorption region of the marking substance, and the fluorescent radiation emitted by the marking substances is detected.

The present invention also relates to liquids which are labeled by the method of the present invention.

It is often necessary to label liquids in order to subsequently, e.g. when used to detect the liquids marked in this way using suitable methods. In this way, for example, heating oil, which is usually tax-privileged, can be distinguished from diesel oil, which is generally subject to higher taxes, or liquid product streams in large-scale plants, such as Oil refineries, mark and track them.

If the marking of the liquids is to be invisible to the human eye, one has to rely on marking substances which absorb outside the visible range of the spectrum and / or emit radiation. Because of the high sensitivity of the detection and the associated possibility of achieving reliable marking with small additions of the marking substance, marking substances which emit the absorbed radiation as fluorescent radiation are of particular importance here. As a rule, this emitted radiation is present 2 a lower frequency than the absorbed radiation (STOKES radiation), in rare cases the same (resonance fluorescence) or even a higher frequency (ATI-STOKES radiation).

The marking of hydrocarbons and hydrocarbon mixtures (e.g. different qualities of diesel and petrol fuels and other mineral oils) is of great (national) economic importance. Since these liquids usually themselves have high absorption and / or fluorescence in the spectral range below approximately 600 nm, it is sensible to use marking substances which absorb and / or fluoresce above approximately 600 nm.

Ideally, therefore, compounds that are to be used as markers have the following basic requirements:

They show strong absorption in the spectral range from 600 to 1200 nm,

in contrast, they have no or only slight absorption or fluorescence in the visible region of the spectrum,

they show a strong emission of fluorescent radiation in the spectral range from about 600 to about 1200 nm,

the emitted fluorescence radiation can also be found at (weight) concentrations of the markers in the relevant one

Detect liquid of less than 1 pp reliably and

they have sufficient in the liquid to be marked

Solubility.

Depending on the specific requirements, one or more of the following points may be important for the compounds that are to be used as markers:

They can be mixed with other markers and any additives present (this also applies to the miscibility of marked and optionally additive liquids),

they are both stable and dissolved in the liquid to be marked under the influence of external conditions, such as temperature, light, moisture etc., stable, 3 they do not have a detrimental effect on the environment, such as internal combustion engines, storage tanks etc. in which they are used and

they are both toxicologically and ecologically compatible.

WO 94/02570 describes the use of markers from the class of metal-free or metal-containing phthalocyanines, metal-free or metal-containing naphthalocyanines, and nickel-dithiolene complexes for marking liquids

A inium compounds of aromatic amines, the methine dyes or the azulene square acid dyes are described which have their absorption maximum in the range from 600 to 1 200 nm and / or a fluorescence maximum in the range from 620 to 1 200 nm. Furthermore, a method is described which essentially consists in detecting the fluorescent radiation of the marking substance present in the liquid, which absorbs radiation in said spectral range. A detector is also described, which is used to detect the marking substance. However, the use of several marking substances at the same time is not explicitly mentioned.

The document US 5,525,516 also describes a method for marking mineral oils with compounds which have fluorescence in the NIR. Substituted phthalocyanines, substituted naphthalocyanines and square or croconic acid derivatives are used as such markers. In the description of this US document (column 3, lines 35 to 40) it is stated that in the context of the described invention one or more mineral oils can be marked not only with one but also with two or more compounds which fluoresce in the IR range. However, it is also pointed out (column 3, lines 41 to 44) that these fluorescent compound (s) should preferably absorb below 850 nm, since above this wavelength the mineral oils showed strong absorption. This document also claims a method for identifying mineral oils which have been labeled with one or more markers. Here, an excitation range (absorption range) for the marked mineral oil or the marking substances contained therein from 670 to 850 nm is specified. Beyond that, however, no further information is provided on how to proceed with more than one marker in the case of marking mineral oils.

A method for marking gasoline is described in US Pat. No. 5,710,046, which is also based on the detection of a fluorescence color fluorescence color which is dissolved in gasoline and is essentially metal-free. 4

Substance runs out. A correspondingly marked gasoline sample is excited with radiation from a wavelength band of 600 to 2500 nm, which detects fluorescent light emitted by the dye in the wavelength band of approximately 600 to 2500 nm and uses the resulting detection signal to identify the marked sample. This document also describes in detail the structure of a detector for detecting the fluorescent dyes in the marked gasoline samples. However, the use of several markers (dyes) is not discussed.

Should liquids, e.g. Hydrocarbons and hydrocarbon mixtures (for example diesel and petrol fuels as well as other mineral oils) from different origins or different manufacturers are marked, so when using only one marking substance per liquid, a large number of different marking substances are required. These must differ sufficiently from one another with regard to their absorption and / or fluorescence behavior so that the liquids can be identified with regard to their provenance and / or their manufacturer. By marking liquids with only one marker, it is also easier for unauthorized third parties to "counterfeit" unmarked liquids by adding the corresponding marker. This is of great importance if chemically and qualitatively equivalent liquids have different tax levies. For example, only heating oil and diesel fuel are mentioned here.

The object of the present invention was therefore to mark liquids by adding more than two marking substances, i.e. to be provided with a "fingerprint" that makes it difficult to readjust the marking.

This object was achieved by a method for marking liquids with at least two marking substances, which is characterized in that the marking substances

absorb in the spectral range from 600 to 1200 nm and as a result emit fluorescent radiation,

have substantially non-overlapping absorption areas and

at least one of the marking substances has a wavelength of the absorption maximum of more than 850 nm. 5

By using at least one marking substance, the absorption range of which is more than 850 nm, a larger wavelength range of absorption / fluorescence for marking liquids is opened up. This makes it possible to use a larger number of marking substances whose absorption areas do not essentially overlap.

"Essentially non-overlapping absorption areas" here means that the respective absorption spectra of any two markers in question, based on comparable conditions (such as the same liquid, the same molar concentration in the marked liquid and the same absorbing layer thickness of the marked ones) Liquid), should not overlap if possible. However, if there is overlap, the value of the extinction coefficient of one marker should not be more than about 5% of the value of the other marker at all wavelengths in the overlap range for each respective wavelength under consideration. This consideration is based on an absorption spectrum based on the blank value. This blank value corresponds to the absorption spectrum of the corresponding pure (unlabeled) liquid measured under comparable conditions.

In the method according to the invention for marking liquids, preference is given to using marking substances whose respective wavelength of the absorption maximum lies in the spectral range from 600 to 1200 nm.

A combination of n marking substances is preferably used in the method according to the invention for marking liquids, where n denotes an integer from 2 to 10, that is to say values of 2, 3, 4, 5, 6, 7, 8, 9 or 10.

A combination of n marking substances is particularly preferably used in the method according to the invention for marking liquids, where n denotes an integer from 2 to 6, that is to say values of 2, 3, 4, 5 or 6.

A combination of n marking substances is very particularly preferably used in the method according to the invention for marking liquids, where n denotes an integer from 2 to 4, that is to say values of 2, 3 or 4.

The markers which absorb in the spectral range from 600 to 1200 nm and consequently emit fluorescent radiation are used in the process according to the invention and in the preferred ones 6

Embodiments in which one uses a combination of n equal to 2 to 10, n equal to 2 to 6 or n equal to 2 to 4 markers, compounds to, which are selected from the group consisting of metal-free and metal-containing phthalocyanines, metal-free and metal-containing naphthalocyanines, nickel -Dithio - len- complexes, amino compounds of aromatic amines, methine dyes, squaric acid dyes and crocodic acid dyes.

The markers which absorb at a wavelength of the absorption maximum in the spectral range from 600 to 1200 nm and consequently emit fluorescent radiation are used in the process according to the invention and in the preferred embodiments in which a combination of n is 2 to 10 , n is from 2 to 6 or n is from 2 to 4 markers, preferably the same compounds used, which are selected from the group consisting of metal-free and metal-containing phthalocyanines, metal-free and metal-containing naphthalocyanines, nickel-dithiolene complexes, aminium compounds of aromatic amines, methine dyes , Square acid dyes and croconic acid dyes.

Markers which absorb at a wavelength of the absorption maximum of more than 850 nm and consequently emit fluorescent radiation are used in the process according to the invention and in the preferred embodiments in which a combination of n is 2 to 10, n is 2 up to 6 or n equals 2 to 4 markers, preferably at least one compound selected from the group consisting of metal-free and metal-containing naphthalocyanines, nickel-dithiolene complexes, aminium compounds of aromatic amines, methine dyes, squaric acid dyes and croconic acid dyes.

Suitable phthalocyanines obey, for example, the formula Ia

(ia),

in the

Me ¹ twice hydrogen, twice lithium, magnesium, zinc, copper, nickel, VO, TiO, A1C1, AlO-Cι-C ₂₀ alkyl, A1NH-Cι-C ₂₀ alkyl, AlN (Cι ~ C ₂₀ alkyl) _2nd , AlO-C ₆ -C ₂₀ aryl, Al-NH-C ₆ -C ₂₀ aryl or A1N (-C ₆ -C ₂₀ aryl) ₂ / AIN-Het, where N-Het is a heterocyclic, saturated or unsaturated is a five-, six- or seven-membered ring which, in addition to at least one nitrogen atom, may also contain one or two further nitrogen atoms and / or a further oxygen or sulfur atom in the ring, which may optionally be one to three times with C 1 -C ₄ -alkyl, phenyl , Benzyl or phenylethyl and which is bonded to the aluminum atom via a (or the) ring nitrogen atom, or Si (OH) ₂ ,

at least 4 of the radicals R ¹ to R ¹⁶ independently of one another for a radical of the formula WX ¹ , where W for a chemical bond, oxygen, sulfur, imino, -CC alkylimino or phenylimino and X ¹ for -CC alkyl or C ₃ -Cι ₀ cycloalkyl, which is optionally interrupted by 1 to 4 oxygen atoms in ether function and can be substituted by phenyl, adamantyl or optionally substituted phenyl, heterocyclic, saturated five-, six- or seven-membered rings, which also have one or two further nitrogen atoms and / or can contain a further oxygen or sulfur atom in the ring, which are optionally mono- to trisubstituted with C 1 -C 4 -alkyl, phenyl, benzyl or phenylethyl and which are bonded to the benzene ring via a (or the) ring nitrogen atom are, stand and

optionally the other radicals R ¹ to R ^{16 are} hydrogen, halogen, hydroxysulfonyl or Cχ-C-dialkylsulfamoyl.

Suitable phthalocyanines also obey, for example, the formula Ib (Ib),

in the

R ¹⁷ and R ¹⁸ or R ¹⁸ and R ¹⁹ or R ¹⁹ and R ²⁰ together each represent a radical of the formula X ² -C ₂ HX ³ , wherein one of the two radicals X ² and X ³ for oxygen and the other for imino or Cι -C ₄ alkylimino, and

R ¹⁹ and R ²⁰ or R ¹⁷ and R ²⁰ or R ¹⁷ and R ¹⁸ each independently represent hydrogen or halogen and

Me ^{1 has} the meaning given above.

Unless they have already been mentioned under the phthalocyanines listed above, further suitable phthalocyanines are shown in US 5,526,516 under general formula I and, for example, in Table 3, and in US 5,703,229 under general formula II and, for example, in Table 3.

Suitable naphthalocyanines obey e.g. of formula II

(II)

9 in

Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁶ , Y ⁷ and Y ⁸ each independently of one another are hydrogen, hydroxy, C ₁ -C ₂ -alkyl, C ₃ -C 8 -cycloalkyl or Cχ-C ₂ o Alkoxy, where the alkyl groups can each be interrupted by 1 to 4 oxygen atoms in ether function and are optionally substituted by phenyl, heterocyclic, saturated five-, six- or seven-membered rings, which also have one or two further nitrogen atoms and / or another May contain oxygen or sulfur atom in the ring, which are optionally mono- to trisubstituted with -C ₄ alkyl, phenyl, benzyl or phenylethyl and which are bonded to the benzene ring via a (or the) ring nitrogen atom,

Y ⁹ , Y ¹⁰ , Y ¹¹ and Y ¹² independently of one another are each hydrogen, C 1 -C 8 -alkyl or C ₁ -C ₂ o -alkoxy, where the alkyl groups can each be interrupted by 1 to 4 oxygen atoms in ether function, halogen, hydroxysulfonyl or Cι-C ₄ -dialkylsulfamoyl and

Me ^{2 has} the meaning of Me ¹ or the rest

γl7

/

Si L

\ γl 8 means, where

Y ¹⁷ and Y ¹⁸ independently of one another in each case j is hydroxy, Cι-C ₂ o-alkoxy, Cι-C ₂₀ alkyl, C ₂ -C ₂ -alkenyl, C ₃ -C ₂ o-alkenyloxy or a radical of formula

γ20

O-Si-OY ¹⁹ γ21

are, wherein Y ^19, the importance of Cι-C ₂ -alkyl, C ₂ -C ₂ o ~ alkenyl or C ₂ o-alkadienyl and Y ²⁰ and Y ²¹ each independently represent the meaning of Cι-Cι alkyl, C ₂ -Cχ alkenyl or the above radical OY ¹⁹ have.

Of particular interest are naphthalocyanines of the formula II in which at least one of the radicals Y ¹ to Y ⁸ are different from hydrogen. 10

Further suitable naphthalocyanines, unless they have already been mentioned under the naphthalocyanines listed above, are shown in US 5,526,516 under general formula II and, for example, in Table 4 and in US 5,703,229 under general formula III and, for example, in Table 4.

Suitable nickel-dithiolene complexes obey e.g. of formula III

(III)

in the

L ¹ , L ² , L ³ and L ⁴ each independently of one another C ₁ -C ₂ -alkyl, which is optionally interrupted by 1 to 4 oxygen atoms in ether function, phenyl, C ₁ -C ₂ o -alkylphenyl, C ₁ -C o ~ alkoxyphenyl , where the alkyl groups can each be interrupted by 1 to 4 oxygen atoms in ether function, or L ¹ and L ² and / or L ³ and L ⁴ each together the rest of the formula

mean.

Suitable aminium compounds obey e.g. of the formula IV

©

A ^nC (IV),

in the

Z ¹ , Z ² , Z ³ and Z ⁴ are each independently of one another C ₁ -C ₂ -alkyl, which is optionally interrupted by 1 to 4 oxygen atoms in ether function, C ₁ -C ₂ o -alkanoyl or a radical of the formula 11

/

\ z «z ⁷

wherein Z ⁶ for hydrogen, -CC ₂ o-alkyl, which is optionally interrupted by 1 to 4 oxygen atoms in ether function, or -C-C ₂ o-alkanoyl, Z ⁷ for hydrogen or -C-C ₂₀ alkyl, which is optionally by 1 to 4 oxygen atoms in ether function is interrupted, and Z ^{8 is} hydrogen, -CC ₂₀ alkyl, which is optionally interrupted by 1 to 4 oxygen atoms in ether function, or halogen, and

A ⁿ ® mean the equivalent of an anion.

Suitable methine dyes obey e.g. Formula V

A ⁿ © (V) n

in which the rings A and B are each optionally benzo-fused independently of one another and can be substituted,

E ¹ and E ² each independently of one another oxygen, sulfur, imino or a radical of the formula

—C (CH ₃ ) ₂ - or —CH = CH—,

D is a radical of the formula

-CE ³ = or —CH = CE ³ —CH =

in which E ^{3 represents} hydrogen, C ₁ -C ₆ -alkyl, chlorine or bromine and E ^{4 represents} hydrogen or C ₁ -C ₆ -alkyl,

Q ¹ and Q ² are each independently phenyl, C ₅ -C ₇ cycloalkyl, C ¹ -C ₂ alkyl which can be interrupted by 1 to 3 oxygen atoms in ether function and optionally by hydroxy, chlorine, 12

Bromine, carboxyl, -CC ₄ alkoxycarbonyl, acryloyloxy, methacryloyloxy, hydroxysulfonyl, Ci - ^ - alkanoylamino, Ci-C _δ -alkylcarbamoyl, -C-C ₆ -alkylcarbamoyloxy or a radical of the formula G® (K) ₃ , in which G represents nitrogen or phosphorus and K represents phenyl, C ₅ -C ₇ cycloalkyl or C 1 -C ₂ alkyl, are substituted,

A ⁿ ® the equivalent of an anion and

n is 1, 2 or 3.

Suitable square acid dyes are e.g. those compounds which are shown in US Pat. No. 5,526,516 under general formula III and exemplarily in Table 2 and in US Pat. No. 5,703,229 under general formula IV and exemplarily in Table 2.

Suitable square acid dyes are also azulene square acid dyes, which e.g. obey Formula VI shown below

Oθ

(VI),

in the

J -C-C ₁₂ alkylene,

T ^{1 is} hydrogen, halogen, amino, hydroxy, C 1 -C ₂ alkoxy, phenyl, substituted phenyl, carboxyl, C 1 -C ₂ alkoxycarbonyl, cyano or a radical of the formula -NT ⁷ -CO-T ⁶ , -CO-NT ⁶ T ⁷ or 0-CO-NT ⁶ T ⁷ , wherein T ⁶ and T ⁷ independently of one another each represent hydrogen, C 1 -C ₂ alkyl, C ₅ -C ₇ cycloalkyl, phenyl, 2, 2, 6, 6- Tetramethyl-piperidin-4-yl or cyclohexylaminocarbonyl, and

T ² , T ³ , T ⁴ and T ⁵ are each independently hydrogen or C_ _. -Ci ₂ alkyl, which is optionally substituted by halogen, amino, Cχ-Cι ₂ - alkoxy, phenyl, substituted phenyl, carboxyl, C ~ -C -alkoxy carbonyl or cyano, 13 with the proviso that when T ^{5 is} hydrogen, the ring positions of the substituents JT ¹ and T ⁴ can also be interchanged on one or both azulene rings within an azulene ring.

Suitable square acid dyes are e.g. also those compounds which obey the formula Via below,

Ar- Arθ (via),

each in the Ar independently of one another for an aromatic or heteroaromatic five- or six-membered ring which is optionally substituted by C ₂ -C -alkoxy, C ₁ -C 8 -alkylamino, C 1 -C ₂ -dialkylamino or Cχ ~ Co ~ alkylthio, such as eg phenyl, naphthyl, thiophene, pyridine or thiazole. The alkyl groups can each be interrupted by 1 to 4 oxygen atoms in ether function and optionally substituted by phenyl.

Ar is preferably phenyl which is mono-, di- or tri-substituted in the 2-, 2,4- or 2,4,6 position with the said radicals. If the phenyl is substituted several times, these radicals are preferably the same. In particular, those compounds are considered in which both Ar are the same.

Suitable croconic acid dyes are e.g. those compounds which are shown in US Pat. No. 5,526,516 under the general formula IV and are listed in Table 5 by way of example.

All alkyl, alkylene or alkenyl radicals occurring in the above formulas can be either straight-chain or branched.

In formula Ia, II, III, IV or Via are suitable C ₁ -C ₂ -alkyl radicals which are optionally interrupted by 1 to 4 oxygen atoms in ether function, for example methyl, ethyl, propyl, isopropyl, butyl, Isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, Tridecyl, 3, 5, 5, 7-tetramethylnonyl, isotridecyl (the above terms isooctyl, isononyl, isodecyl and isotridecyl are trivial names and come from the alcohols obtained after oxo synthesis - cf. Ull anns 14

Encyclopedia of Industrial Chemistry, 4th edition, volume 7, pages 215 to 217, and volume 11, pages 435 and 436), tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, ^' 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 3-butoxypropyl, 2- or 4-methoxybutyl, 2 - or 4-ethoxybutyl, 2- or 4-propoxybutyl, 2- or 4-butoxybutyl, 3, 6-dioxaheptyl, 3, 6-dioxaoctyl, 4, 8-dioxanonyl, 3, 7-dioxaoctyl, 3, 7-dioxanonyl, 4, 7-dioxaoctyl, 4, 7-dioxanonyl, 4, 8-dioxadecyl, 3, 6, 8-trioxadecyl, 3, 6, 9-trioxaundecyl,

3, 6, 9, 12-tetraoxatridecyl or 3, 6, 9, 12-tetraoxatetradecyl.

In formula Ia or II are suitable C ₃ -Cιrj-cycloalkyl radicals branched or unbranched cycloalkyl radicals which are optionally interrupted by 1 to 4 oxygen atoms in ether function, for example cyclopropyl, cyclobutyl, cyclopentyl, tetrahydrofranyl, cyclohexyl, tetrahydropyranyl, cycloheptyl, oxepanyl, 1 Methyl - cyclopropyl, 1-ethylcyclopropyl, 1-propylcyclopropyl, 1-butylcyclopropyl, 1-pentylcyclopropyl, 1-methyl-1-butylcyclopropyl, 1, 2-dimethylcyclypropyl, 1-methyl-2-ethylcyclopropyl, cyclooctyl, cyclononyl or cyclodecyl.

In formula Ia, Ib or II, suitable C ₆ -C ₂ o ~ aryl radicals in the AlO-C ₆ -C ₂₀ aryl, Al-NH-C ₆ -C ₂₀ aryl or A1N (-C ₆ -C ₂₀ aryl) ₂ - groupings of Me ¹ or Me ^2, for example optionally with up to two C ₇ alkyl, with up to three C 1 alkyl, with up to four C ₃ C ₃ alkyl or phenyl substituted with up to five methyl or ethyl radicals or optionally with up to two Cχ-C5-alkyl, with up to three Cχ-C ₃ alkyl- or with up to four methyl or ethyl radicals substituted naphthyl, where such optionally present alkyl substituents are indicated under the previously listed ^c i ^"c ~ ₂₀ alkyl radicals.

In formula Ia, Ib or II, suitable N-Het in the A1N-Het groups of Me ¹ or Me ^{2 are derived} from, for example, pyrrole, pyrrolidine, pyrazole, pyrazolidine, imidazole, imidazoline, 1H-1, 2, 3- Triazole, 1, 2,3-triazolidine, 1H-1, 2, 4-triazole, 1, 2, 4-triazolidine, pyridine, piperidine, pyrazine, piperazine, pyridazine, morpholine, 1H-azepine, 2H-azepine, azepane, Oxazole, oxazolidine, thiazole, thiazolidine, 1,2,3-, 1,2,4- or 1,3,4-oxadiazole, 1,2,3-, 1,2,4- or

1, 3, 4-oxadiazolidine, 1,2,3-, 1,2,4- or 1, 3, 4-thiadiazole or 1,2,3-, 1,2,4- or 1, 3, 4- Thiadiazolidine, where the heterocyclic rings are optionally substituted one to three times with C 1 -C ₄ -alkyl, phenyl, benzyl or phenylethyl. Corresponding, where appropriate, Cχ-C-alkyl radicals have already been mentioned above for the -C-C ₂ o-alkyl radicals. 15

In formula Ia or II, suitable heterocyclic, ring-shaped radicals for R ¹ to R ¹⁶ or Y ¹ to Y ^{8 are derived} from heterocyclic, saturated five-, six- or seven-membered rings which also have one or two further nitrogen atoms and / or can contain another oxygen or sulfur atom in the ring, for example pyrrolidine, pyrazolidine, imidazoline, 1, 2, 3-triazolidine, 1, 2, 4-triazolidine, piperidine, piperazine, morpholine, azepane, oxazolidine, thiazolidine, 1 , 2,3-, 1,2,4- or 1, 3, 4-oxadiazolidine, or 1,2,3-, 1,2,4- or 1, 3, 4-thiadiazolidine, the heterocyclic rings optionally substituted one to three times with C 1 -C 4 alkyl, phenyl, benzyl or phenylethyl. Corresponding C 1 -C 8 -alkyl radicals which may be considered have already been mentioned above for the C 1 -C ₂₀ -alkyl radicals.

In formula Ia, II or Via is suitable C ₁ -C ₂ -alkyl which is substituted by phenyl, for example benzyl or 1- or 2-phenylethyl.

In formula II, III, IV or Via are suitable C ₁ -C ₂ -alkoxy radicals which are optionally interrupted by 1 to 4 oxygen atoms in ether function, for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentyloxy, hexyloxy, heptyloxy, Octyloxy, 2-ethylhexyloxy, isooctyloxy, nonyloxy, isononyloxy, decyloxy, isodecyloxy, undecyloxy, dodecyloxy, tridecyloxy, isotridecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy, heptadecyloxy, octa-decyloxy, methoxy-ethoxy-ethoxy-oxyoxy-nonoxy 2-propoxyethoxy, 2-isopropoxyethoxy, 2-butoxyethoxy, 2- or 3-methoxypropoxy, 2- or 3-ethoxypropoxy, 2- or 3-propoxypropoxy, 2- or 3-butoxypropoxy, 2- or 4-methoxybutoxy, 2 - or 4-ethoxybutoxy, 2- or 4-propoxybutoxy, 2- or 4-butoxybutoxy, 3, 6-dioxaheptyloxy, 3, 6-dioxaoctyloxy, 4, 8-dioxanonyloxy, 3, 7-dioxaoctyloxy, 3, 7- Dioxanonyloxy, 4, 7-Dioxaoctyloxy, 4, 7-Dioxanonyloxy, 4, 8-Dioxadecyloxy, 3, 6, 8-Trioxadecyloxy, 3, 6, 9-Trioxaundecyloxy, 3, 6, 9, 1 2-tetraoxatridecyloxy or 3,6,9, 12-tetraoxatetradecyloxy.

In formula II or via is suitable -C ₂ -C ~ alkoxy which is substituted by phenyl, for example benzyloxy or 1- or 2-phenylethoxy.

In formula Ia, III or VI, suitable substituted phenyl is, for example, phenyl substituted by C ₁ -C ₆ -alkyl, C ₁ -C ₆ alkoxy, hydroxy or halogen. As a rule, 1 to 3 substituents can occur. In particular, the phenyl is substituted with 1 or with 2 substituents Ci-Cβ-alkyl or -CC ₆ alkoxy. In the case of mono substitution, the substituent is preferably in para 16

Position. In the case of disubstitution, the substituents are preferably in the 2,3-, 2,4-, 3,4- and 3,5-position.

Halogen in formula Ib, II, IV or VI is e.g. Fluorine, chlorine or bromine.

W radicals in formula Ia and X ² or X ³ in formula Ib are, for example, methylimino, ethylimino, propylimino, isopropylimino or butylimino.

R ¹ to R ¹⁶ in formula Ia and Y ⁹ to Y ¹² in formula II are, for example, dimethylsulfamoyl, diethylsulfamoyl, dipropylsulfamoyl, di-butylsulfamoyl or N-methyl-N-ethylsulfamoyl.

C ₂ -Co-alkenyl and C-Co-alkanedienyl in formula II is, for example

Vinyl, allyl, prop-1-en-l-yl, methallyl, ethallyl, but-3-en-l-yl, pentenyl, pentadienyl, hexadienyl, 3, 7-dimethylocta-l, 6- dien-1-yl, Undec-10-en-l-yl, 6, 10-dimethylundeca-5, 9-dien-2-yl, octadec-9-en-l-yl, octadeca-9, 12-dien-1-yl, 3, 7, 11, 15-tetramethylhexadec-l-en-3-yl or Eicos-9-en-l-yl.

C ₃ -Co ~ alkenyloxy in formula II is, for example, allyloxy, methallyloxy but-3-en-l-yloxy, undec-10-en-l-yloxy, octadec-9-en-l-yloxy or EICOS-en-9, -l-yloxy.

Z ⁶ in formula IV means, for example, formyl, acetyl, propionyl, butyryl, isobutyryl, pentanoyl, hexanoyl, heptanoyl, octanoyl or 2-ethylhexanoyl.

If the rings A and / or B are substituted in formula V, the substituents can be, for example, -C ₆ alkyl, phenyl -C ₆ alkoxy, phenoxy, halogen, hydroxy, amino, Ci-Ce mono- or Dialkylamino or cyano come into consideration. The rings are usually 1 to 3 times substituted.

Residues E ³ , E ⁴ , Q ¹ and Q ² in formula V are, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, neopentyl, tert-pentyl or hexyl.

Residues Q ¹ and Q ² are furthermore, for example, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, 2-methoxyethyl, 2-ethoxyethyl, 2 - or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2-hydroxyethyl, 2- or 3-hydroxypropyl, 2-chloroethyl, 2-bromoethyl, 2- or 3-chloropropyl, 2- or 3-bromopropyl, 2- Carboxyethyl, 2- or 3-carboxypropyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 2- or 3-methoxycarbonylpropyl, 2- or 3-ethoxy- 17 carbonylpropyl, 2-acryloyloxyethyl, 2- or 3-acryloyloxypropyl, 2-methacryloyloxyethyl, 2- or 3-methacryloyloxypropyl, 2-hydro- xysulfonylethyl, 2- or 3-Hydroxysulfonylpropyl, 2-Acetylaminoe- ^'methyl, 2- or 3- Acetylaminopropyl, 2-methylcarbamoylethyl, 2-ethylcarbamoylethyl, 2- or 3-methylcarbamoylpropyl, 2- or 3-ethylcarbamoylpropyl, 2-methylcarbamoyloxyethyl, 2-ethylcarbamoyloxyethyl, 2- or 3-methylcarbamoyloxypropyl, 2- or 3-ethylpropyl, 2- (trimethylammonium) ethyl, 2- (triethylammonium) ethyl, 2- or 3- (trimethylammonium) propyl, 2- or 3- (triethylammonium) propyl, 2- (triphenylphosphonium) ethyl or 2- or 3- (triphenylphosphonium) ropyl .

pj £ ⁾ ± _n Formula IV or V is derived, for example, from anions of organic or inorganic acids. For example, methanesulfonate, 4-methylbenzenesulfonate, acetate, trifluoroacetate, heptafluorobutyrate, chloride, bromide, iodide, perchlorate, tetrafluoroborate, nitrate, hexafluorophosphate or tetraphenylborate are particularly preferred.

Residues J in formula VI are e.g. Methylene, ethylene, 1,2- or 1,3-propylene, 1,2-, 1,3-, 2,3- or 1,4-butylene, pentaethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene , Undecamethylene or dodecamethylene.

T ² , T ³ , T ⁴ and T ⁵ in formula VI are, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 2-methylbutyl , Hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, undecyl, dodecyl, fluoromethyl, chloromethyl, di-fluoroethyl, trifluoroethyl, trichloromethyl, 2-fluoroethyl, 2-chloroethyl, 2 -Bromethyl, 1, 1, 1-trifluoroethyl, heptafluoropropyl, 4-chlorobutyl, 5-fluoropentyl, 6-chlorhexyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 2-cyanobutyl, 4-cyanobutyl, 5-cyanopentyl, 6 Cyanohexyl, 2-aminoethyl, 2-aminopropyl, 3-aminopropyl, 2-aminobutyl, 4-aminobutyl, 5-aminopentyl, 6-aminohexyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl,

4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-methoxypropyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxyb tyl, 4 Isopropoxybutyl, 5-ethoxypentyl, 6-methoxyhexyl, benzyl, 1-phenylethyl, 2-phenylethyl, 4-chlorobenzyl, 4-methoxybenzyl, 2- (4-methylphenyl) ethyl, carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, 5-carboxypentyl, 6-carboxyhexyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 3-methoxycarbonylpropyl, 3-ethoxycarbonylpropyl, 4-methoxycarbonylbutyl, 4-ethoxycarbonylbutyl 18th

5-methoxycarbonylpentyl, 5-ethoxycarbonylpentyl, 6-methoxycarbonylhexyl or 6-ethoxycarbonylhexyl.

T ¹ in formula VI is, for example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, isopentyloxycarbonyl, neopentyloxycarbonyl, tert-pentyloxycarbonyl, hexyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl, octyloxycarbonyl , Nonyloxycarbonyl, isononyloxycarbonyl, decyloxycarbonyl, isodecyloxycarbonyl, undecyloxycarbonyl, dodecyloxycarbonyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentyloxy, hexyloxy, acetylamino, carbamoyl, mono-, or dimethylcarbo-carbonyl, mono-carboxy-mono-carbonyl , Phenylcarbamoyl, dimethylcarbamoyloxy or diethylcarbamoyloxy.

The naphthalocyanines of the formula Ha are particularly noteworthy as markers

(Ha)

in the

Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁶ , Y ⁷ and Y ⁸ independently of one another are each hydrogen, hydroxy, C 1 -C ₄ -alkyl or C ₁ -C ₂ o-alkoxy and

Me ^{2 has} the meaning of Me ¹ or the rest

γ ² o

I.

S i— (-0 - S i - 0 - Y ¹⁹ ) ₂ γ21 19 corresponds to, in which R ^{19 is} Cχ-Cι ₃ alkyl or Cιo-C ₂ o-alkadienyl and Y ²⁰ and Y ²¹ are each independently of the other Cι-Cι ₃ alkyl or C ₂ -C alkenyl.

Particularly noteworthy are naphthalocyanines of the formula Ha, in which Y ¹ , Y ² , Y ³ , Y, Y ⁵ , Y ⁶ , Y ⁷ and Y ⁸ each independently of one another are hydroxy, C 1 -C ⁸ -alkoxy, in particular C 1 -C 8 -alkoxy mean. The alkoxy radicals can be the same or different. Also of particular note are naphthalocyanines of the formula Ha, in which Me ^{2 is} twice hydrogen.

Also to be emphasized as markers are nickel-dithiolene complexes of the formula III in which L ¹ , L ² , L ³ and L ⁴ are each independently phenyl, C ₁ -C ₂ -alkylphenyl, C 1 -C 8 -alkoxyphenyl or by hydroxy and -C-C ₂₀ alkyl substituted phenyl or L ¹ and L ² and L ³ and L ⁴ each together the rest of the formula

mean.

Particularly noteworthy are nickel-dithiolene complexes of the formula III, in which L ¹ and L ^{4 are} each phenyl and L ² and L ^{4 are} each a radical of the formula 4- [CH ₅ -C (CH ₃ ) ₂ ] -C ₆ H mean.

The phthalocyanines of formula Ia are known per se and e.g. described in DE-B-1 073 739 or EP-A-155 780 or can be carried out according to methods known per se, such as are used in the production of phthalocyanines or naphthalocyanines and as described, for example, in F.H. Moser, A.L. Thomas "The Phthalocyanines", CRC Press, Boca Rota, Florida, 1983, or J. Am. Chem. Soc. Volume 106, pages 7404 to 7410, 1984. The phthalocyanines of formula Ib are also known per se and e.g. in EP-A-155 780 or can be obtained according to the methods of the above-mentioned prior art (Moser, J.Am. Chem. Soc.).

The naphthalocyanines of the formula II are likewise known per se and are described, for example, in EP-A-336 213, EP-A-358 080,

GB-A-2 168 372 or GB-A-2 200 650 or can be according to 20 the methods of the above-mentioned prior art (Moser, J.Am. Chem. Soc.) Can be obtained.

The nickel-dithiolene complexes of the formula III are also known per se and are described, for example, in EP-A-192 215.

The aminium compounds of formula IV are also known per se and e.g. in US-A-3 484 467 or can be obtained according to the methods mentioned therein.

The methine dyes of formula V are also known per se and e.g. described in EP-A-464 543 or can be obtained according to the methods mentioned therein.

The preparation of the squaric acid dyes is described in US 5,525,516 and US 5,703,229 and the literature cited therein.

The production of the croconic acid dyes is described in US 5,525,516 and the literature cited therein.

The azulene square acid dyes of the formula VI are also known per se and are e.g. in EP-A-310 080 or US-A-4 990 649 or can be obtained according to the methods mentioned therein.

Liquids which can be labeled as markers with a combination of at least two of the compounds specified above are usually organic liquids, for example

Alcohols, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, pentanol, isopentanol, neopentanol or hexanol,

Glycols, such as 1,2-ethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 2,3- or 1,4-butylene glycol, di- or triethylene glycol or di- or tripropylene glycol,

Ethers, such as methyl tert-butyl ether, 1,2-ethylene glycol mono- or dimethyl ether, 1,2-ethylene glycol mono- or diethyl ether, 3-methoxypropanol, 3-isopropoxypropanol, tetrahydrofuran or dioxane,

Ketones, such as acetone, methyl ethyl ketone or diacetone alcohol, 21

Esters, such as methyl acetate, ethyl acetate, propyl acetate or butyl acetate,

aliphatic or aromatic hydrocarbons such as pentane, hexane, heptane, octane, isooctane, petroleum ether, toluene, xylene, ethylbenzene, tetralin, decalin, dimethylnaphthalene, white spirit,

natural oils such as olive oil, soybean oil or sunflower oil, or natural or synthetic motor, hydraulic or gear oils, e.g. Vehicle engine oil or sewing machine oil, or brake fluids

and mineral oils such as gasoline, kerosene, diesel oil or heating oil.

The above-mentioned compounds are used particularly advantageously for marking mineral oils, for which marking is also required, e.g. for tax reasons. In order to keep the costs of labeling low but also to minimize possible interactions of the marked mineral oils with other ingredients that may be present, the aim is to keep the amount of marking substances as low as possible. Another reason for keeping the amount of marking substances as small as possible can be to prevent their possible damaging influences, for example on the fuel inlet and exhaust outlet area of internal combustion engines.

As already mentioned above, efforts are generally made to use such compounds as marking substances for the marking of liquids which result in a high fluorescence quantum yield, that is to say they emit a large part of the absorbed radiation quanta as fluorescence radiation quanta.

These compounds to be used as markers are added to the liquids in such quantities that reliable detection is ensured. Usually, the (weight-based) total content of markers in the marked liquid is approximately 0.1 to 5000 ppb, preferably 1 to 2000 ppb and particularly preferably 1 to 1000 ppb.

To mark the liquids, the compounds mentioned above as markers (or their combinations of at least two markers) are generally added in the form of solutions (stock solutions). In the case of mineral oils in particular, aromatic hydrocarbons such as toluene, xylene or higher-boiling aromatic mixtures are preferably suitable as solvents for preparing these stock solutions. 22

In order to avoid too high a viscosity of such stock solutions (and thus poor metering and handling), a total concentration of the marking substances of 0.5 to 50% by weight, based on the total weight of these stock solutions, is generally chosen.

Another object of the present invention is a method for the detection of marking substances in liquids which have been marked according to the method according to the invention and its preferred embodiments, which is characterized in that a radiation source is used which emits radiation in the absorption areas of all marking substances , and the fluorescent radiation emitted by the markers is detected.

Another object of the present invention is a method for the detection of marking substances in liquids which have been marked according to the method according to the invention and its preferred embodiments, which is characterized in that for each individual marking substance an appropriate radiation source is used, which radiation is emitted in the absorption region of the marking substance and the fluorescent radiation emitted by the marking substances is detected.

The basic equipment for excitation and detection of fluorescence in a liquid labeled according to the invention contains:

a sample cuvette containing the marked liquid,

an excitation unit (A) which contains:

αi) a radiation source, which is usually provided with collimator optics, and

α ₂ ) usually a plane mirror, which is located opposite the radiation source on the side of the sample cell facing away from the radiation source and serves to increase the intensity radiated into the sample by reflection of the transmitted radiation,

a detection unit (D) which contains:

δi) a photodetector (usually provided with collimator optics), in front of which there are usually optical filters (eg edge or interference filters) and possibly NIR polarizers, and which is arranged in such a way that its 23

Direction of emitted fluorescence radiation strikes it (or is imaged) and is detected, and

δ ₂ ) usually a concave mirror, which is located opposite the photodetector on the side of the sample cell facing away from the photodetector and serves to reflect the fluorescence radiation emitted in the opposite direction (away from the photodetector) and thus to increase the detection sensitivity.

In principle, such a structure is shown in the drawing in WO 94/02570 (deviating from the beam direction of the radiation source). However, the detection of the fluorescence radiation does not have to be perpendicular, but can be carried out at almost any angle to the beam direction. However, angles of 0 ° or 180 ° do not make sense.

With regard to the following explanations, the following definitions should apply:

Excitation and detection units in the general sense are referred to as A and D (see above). Markers in the general sense are called M.

An excitation unit which is specially adapted to one of the marking substances Mμ by means of a corresponding radiation source (i.e. the radiation source emits radiation in the absorption region of the marking substance Mμ) is designated Aμ. Because e.g. the number n of markers in the preferred embodiments is 2 to 10 or 2 to 6 or 2 to 4, μ can accordingly assume whole numerical values from 1 to 10 or 1 to 6 or 1 to 4.

A special detection unit, which e.g. by means of appropriate optical filters (and possibly polarizers), specially adjusted to the emitted fluorescent radiation of one of the marking substances Mμ, is denoted by Dμ (or also as detection channel μ).

For example, assign the three marking substances Ml, M2 and M3 to AI, A2 and A3 or Dl, D2 and D3.

If the adaptation to the respective marking substance Mμ takes place within an excitation unit A only by using a corresponding radiation source αiμ (ie this emits radiation in the absorption region of the marking substance Mμ), this becomes the case for n marking substances with A (1, 2 ), A (l, 2,3), etc. 24 to A (l, 2,3, ..., 9,10) or A (l, 2), A (l, 2,3) etc. to A (l, 2,3, ..., 5,6) or A (1, 2), A (1, 2, 3), A (1, 2, 3, 4), where, for example, n is 2 to 10 or 2 to 6 or 2 to 4.

Analogously, for a detection unit Dμ, in which the adaptation to the emitted fluorescent radiation of the respective marking substance Mμ takes place through the use of appropriate photodetectors and / or optical filters (and possibly polarizers), in the case of n marking substances, the designations D (l, 2), D (l, 2,3), etc. to D (1, 2, 3, ..., 9, 10) or D (l, 2), D (l, 2,3) etc. to D (1, 2, ..., 5, 6) or D (1, 2), D (1, 2, 3), D (1, 2, 3, 4), where, for example, n is again the same 2 to 10 or 2 to 6 or 2 to 4.

If n markers Mμ, where n is again 2 to 10 or 2 to 6 or 2 to 4, respectively, are excited and detected one after the other with the units Aμ and Dμ respectively adapted to them, this is indicated by the notation "Al / Ml / Dl, A2 / M2 / D2, ... "etc. to" ... A9 / M9 / D9, A10 / M10 / D10 "or" Al / Ml / Dl, A2 / M2 / D2, .. . "etc. to" ... A5 / M5 / D5, A6 / M6 / D6 "or" Al / Ml / Dl, A2 / M2 / D2, A3 / M3 / D3, A4 / M4 / D4 " brought. In a shorter form this can also be done by "AI / Dl, A2 / D2, ..." etc. to "... A9 / D9, A10 / D10" or "AI / Dl, A2 / D2, ... "etc. to" ... A5 / D5, A6 / D6 "or" AI / Dl, A2 / D2, A3 / D3, A4 / D4 "because the notation of Aμ / Dμ refers to the marking material Mμ implies.

If n markers Mμ are excited simultaneously with n units Aμ and at the same time their emitted fluorescence radiation is detected with n units Dμ, this is done with

"A1 / A2 /.../ An / Ml / M2 /.../ Mn / Dl / D2 /.../ Dn" or also shorter with "A1 / A2 /.../ An / Dl / D2 / ... / Dn ".

If n markers are excited simultaneously with n units Aμ and at the same time their emitted fluorescence radiation with a unit D, e.g. a multi-wavelength detector (consisting of an optical, dispersive element, such as a prism or grating, and a line or area detector), this is detected with "A1 / A2 / ... / An / Ml / M2 / ... / Mn / D "or shorter with" A1 / A2 /.../ An / D ".

Basically, a distinction must be made between the two cases, that the excitation of the labeled sample by the units A

I) in the same sample volume or

II) takes place in different sample volumes. 25th

In case I), the following methods and exemplary construction options of the detection devices can be used (n assumes, for example, the values from 2 to 10 or 2 to 6 or 2 to 4):

1.1) AI / Dl, A2 / D2, ..., An-l / Dn-1, An / Dn (the n markers are excited or detected by their respective units Aμ or Dμ).

a) The structure corresponds essentially to the structure mentioned at the outset and shown in WO 94/02570. The difference is that appropriately adapted units Aμ or Dμ are used for each marker Mμ. This can be done radially around the sample cuvette by the spatially offset arrangement of several pairs of units Aμ and Dμ corresponding to the number of markers to be detected. The latter then preferably has a circular cross section. However, the sample volumes (or sample paths) irradiated by the units Aμ are not - in the strict sense - identical. However, the excitation beams (lying in one plane) intersect in a common piece of the sample volume. The combination of excitation and detection of the n marking substances Mμ can be carried out either in succession or simultaneously.

b) Another possible structure is, for example, that the radiation sources αiμ or photodetectors δiμ

Units Aμ and Dμ are located on the corresponding carousels (instead of individual plane mirrors αμ or concave mirrors δ ₂ μ, it makes sense to use only one fixed plane or concave mirror in this case). To detect the marking substance Mμ, the corresponding radiation source αiμ or the corresponding photodetector δiμ is moved into the excitation or detection position by rotating the respective carousels. The beam path through the marked sample and the irradiated sample volume are identical for each marking substance to be determined. The combination of excitation and detection of the n markers Mμ can only be done one after the other.

c) If, for example, a cylindrical sample cuvette is used which can be closed either at one or both ends with windows made of the same material as the cuvette or which is closed at both ends and preferably has side sample inlets and outlets, so a modified structure can be created. Similar to b), the radiation sources αiμ of the units Aμ can be located on a carousel (instead of individual plane mirrors α μ, it makes sense to use only a fixed plane mirror). The respective unit Aμ then radiates 26 parallel to the longitudinal axis of the cuvette. Radially thereto (and therefore always perpendicular to the beam direction of the excitation radiation), the respective units Dμ blank (this time of course with ^'their respective subunits δ ₂ μ) for detecting the fluorescence radiation emitted respectively placed around the sample cuvette. The combination of excitation and detection of the n markers Mμ can only take place in succession (of course, the detection of the fluorescence radiation emitted simultaneously by several markers can be carried out simultaneously by the units Dμ).

1.2) A / D1, A / D2, ..., A / Dn-1, A / Dn (all n markers Mμ are excited simultaneously by a "polychromatic" radiation source and detected by means of their respective detection channel Dμ).

a) The structure can be similar to that described in b) under 1.1). Instead of a corresponding carousel for the subunits αiμ, however, a polychromatic excitation unit A is used. The detection takes place according to the structure described under b) of I.l). The combination of excitation and detection of the n markers Mμ can only be done one after the other.

b) If, for example, a cylindrical sample cuvette is used based on the structure described in c) under I.l), unit A irradiates parallel to the longitudinal axis of the cuvette. Radially (and thus perpendicular to the beam direction of the excitation radiation) the respective units Dμ can be placed around the sample cell. The combination of excitation and detection of the n marking substances Mμ can be carried out either in succession or simultaneously.

1.3) A1 / D, A2 / D, ..., An-l / D, An / D (the n markers Mμ are each excited by their corresponding unit Aμ and detected with a detection unit, e.g. a multi-wavelength detector).

a) The structure can be similar to that described in b) under II). Instead of a corresponding carousel for the photo detectors δ _x μ, however, only one detection unit D, for example a multi-wavelength detector, is used. The excitation takes place in accordance with the structure described under b) of II). The combination of excitation and detection of the n markers Mμ can only be done one after the other. 27 b) If, based on the structure described in c) under II), for example a cylindrical sample cuvette is used, the unit D detects the fluorescence radiation emitted in each case parallel to the longitudinal axis of the cuvette. Radially (and therefore perpendicular to the longitudinal axis of the cuvette), the respective units Aμ (together with their corresponding plane mirrors α ₂ μ) can be placed around the sample cuvette. The combination of excitation and detection of the n marking substances Mμ can be carried out either in succession or simultaneously.

The design options mentioned here are therefore comparable to those mentioned in a) and b) of point 1.2) and differ only in the spatial exchange of the excitation and detection unit (s).

1.4) A (l, 2, ..., nl, n) / Dl, A (l, 2, ..., nl, n) / D2, ..., A (l, 2, ..., nl, n) / Dn-1, A (1, 2, ..., n-1, n) / Dn (the n markers Mμ are each excited and detected by means of their respective detection channel Dμ).

a) The structure can be similar to that described in a) under 1.2). Instead of a corresponding carousel for the radiation sources αμ, an excitation unit A is used, which e.g. (Case ai) contains interchangeable radiation sources αiμ. Furthermore, A can also contain several radiation sources αiμ, the respective radiation, e.g. (Case a) using optical fibers or optical fiber bundles or collinearly superimposing the individual beams of the radiation sources using optical elements, such as e.g. Beam splitter, dichroic beam splitter, grating, etc., is directed so that it enters the sample cell at the same location in each case. The respective fluorescence radiation is detected in accordance with the structure described under a) of 1.2). The combination of excitation and detection of the n markers Mμ can only be done one after the other.

b) If, based on the structure described in c) under II), for example a cylindrical sample cuvette is used, a unit A, as described under a) (case ai or case a ₂ ), radiates parallel to the longitudinal axis of the cuvette. Radially (and thus perpendicular to the beam direction of the excitation radiation) the respective units Dμ can be placed around the sample cell. With a unit A corresponding to case ai, the combination of excitation and detection of the n markers Mμ can only be carried out one after the other. With a unit A corresponding to case a ₂ , the combination of excitation and detection 28 tion of the n marking substances Mμ take place successively and potentially also simultaneously.

1.5) Al / D (l, 2, ..., nl, n), A2 / D (1,2, ..., n-1, n), ..., An-1 / D (l, 2, ..., nl, n), An / D (l, 2, ..., nl, n) (the n markers Mμ are each excited and detected by their corresponding unit Aμ).

a) The structure can be similar to that described in b) under II). Instead of a corresponding carousel for the photodetectors δiμ, however, a detection unit D is used which, for example (case ai), contains interchangeable photodetectors and / or interchangeable optical filters (and possibly polarizers) δiμ. However, D can also contain a plurality of photodetectors δiμ, to which the respective emitted fluorescent radiation, for example (case a ₂ ), is fed by means of optical fibers or optical fiber bundles. The excitation takes place in accordance with the structure described under b) of II). The combination of excitation and detection of the n markers Mμ can only be done one after the other.

b) If, based on the structure described in c) under II), a cylindrical sample cuvette is used, for example, a unit D, as described under a) (case ai or case a ₂ ), detects the one emitted parallel to the longitudinal axis of the cuvette Fluorescence radiation. Radially to this (and thus perpendicular to the longitudinal axis of the cuvette), the respective units Aμ can be placed around the sample cuvette. With a unit D in accordance with case ai, the combination of excitation and detection of the n marking substances Mμ can only take place in succession. With a unit D corresponding to case a ₂ , the combination of excitation and detection of the n marking substances Mμ can be carried out successively and potentially simultaneously.

1.6) A (1, 2, ..., n-1, n) / D (1, 2 n-1, n) (the n markers Mμ are each excited and detected).

The construction can be carried out using an excitation unit A, which, for example (case ai) contains exchangeable radiation sources αiμ or radiation sources αiμ, their respective radiation, for example (case a ₂ ) by means of optical fibers or optical fiber bundles or collinear superimposition of the individual beams of the radiation sources by means of optical elements, such as beam price, dichroic beam splitters, gratings, etc., is guided so that it enters the sample cell at the same location in each case. Correspondingly, a detection unit D can be used which, for example (case ai), has interchangeable photodetectors and / or interchangeable optical filters (and possibly polarizers) δiμ 29 contains or several photodetectors δiμ, to which the respective emitted fluorescent radiation, for example (case a) by means of optical fibers or optical fiber bundles, is fed. ^■ for the cases A (case aι) / D (case a _x), A (case aι) / D (case _a2) and A (case a) / D (case ai), the combination of excitation and detection of the n Markers Mμ only be made one after the other. In case A (case a ₂ ) / D (case a ₂ ), the combination of excitation and detection of the n marking substances Mμ can be carried out successively and potentially simultaneously.

The geometric relationship of the excitation and detection units to one another essentially corresponds to the conditions described under point a) of I.l) and the relationships described in WO 94/02570.

1.7) A1 / A2 /.../ An-1 / An / Dl / D2 /.../ Dn-l / Dn (the n marking substances Mμ are excited or detected simultaneously by their corresponding units Aμ or Dμ).

The simultaneous excitation or detection of the n markers can in principle be carried out with the geometric conditions as described under point II) in a), point 1.2) in b), point 1.3) in b), point 1.4) in case a ₂ of b), point 1.5) in case a ₂ of b) and point 1.6) in case A (case a) / D (case a ₂ ).

In case II), i.e. The excitation takes place in different sample volumes, the following methods and exemplary construction options of the detection devices can be used (n assumes, for example, the values from 2 to 10 or 2 to 6 or 2 to 4):

II.1) AI / Dl, A2 / D2, ..., An-l / Dn-1, An / Dn (the n marking substances Mμ are each excited or detected by their corresponding units Aμ or Dμ).

The arrangement of the respective pairs Aμ / Dμ essentially corresponds to the geometry explained in point II) in a) and to the geometry shown in WO 94/02570. Ie the optical axis of the unit Aμ (corresponding to the direction of the excitation beam) and the optical axis of the corresponding unit Dμ lie in a plane on which the longitudinal axis of the sample cell is perpendicular. These two optical axes form an angle χ, which is between 0 ° and 180 °, whereby the following should be defined: when looking from the unit Aμ in its beam direction, this angle should be + χ or -χ if the corresponding unit Dμ right or left of this 30th

Viewing direction. This is symbolized by the notation Aμ (+) Dμ or Aμ (-) Dμ, i.e. A1 (+) D1, A2 (+) D2, A3 (+) D3 etc. or A1 (-) D1, A2 (-) D2, A3 (-) D3 etc. The excitation (and detection) of spatially different sample volumes takes place in such a way that the respective pairs Am / Dm are arranged in parallel planes. The order of the levels can be in the form

Al (+) D1, A2 (+) D2, A3 (+) D3, ..., An (+) Dn (equivalent to this in the form Al (-) D1, A2 (-) D2, A3 (-) D3 , ..., An (-) Dn) or, for example, in the form A1 (+) D1, A2 (-) D2, A3 (+) D3, ..., An-l (- / +) Dn-1 , On (+/-) Dn. If e.g. the units Aμ are arranged in a row, the units Dμ in the former case are also arranged in a row on one (the "right") side, in the latter case alternately in two rows on opposite sides of the sample cuvette. A shift of the levels against each other is also conceivable (translation). However, this is usually only considered if the excitation radiation emitted by the units Aμ still strikes the outside of the sample cell perpendicularly. This is usually guaranteed in the case of cuvettes with a rectangular cross section, but not in the case of those with a round cross section.

These planes can also be rotated relative to one another (rotation). When looking (projection) along the longitudinal axis of the cuvette, the optical axes belonging to two adjacent units Aμ form an angle that is between 0 and 360 °. For example, in the case of n equal to 2, 3, 4, 5 or 6 (and with a regular, helical arrangement), corresponding angles between adjacent units Aμ of 180, 120, 90, 72 or 60 ° result. For n equal to 3, 4, 5 or 6, complementary angles of 240, 270, 288 or 300 ° (or -120, -90, -72 or -60 °) imply a corresponding opposite helicity in the arrangement ( in the case of n equal to 2, ie not given 180 °). It should also be noted that here, too, the levels do not only correspond to the sequence A1 (+) D1, A2 (+) D2, A3 (+) D3, ..., An (+) Dn (equivalent to this in the sequence A1 (-) D1, A2 (-) D2, A3 (-) D3, ..., An (-) Dn) but also, for example, in the sequence A1 (+) D1, A2 (-) D2, A3 (+) D3 , ..., An-l (- / +) Dn-l, An (+/-) Dn. For n equal to 2 (180 °) or 4 (90 °) a cuvette with a rectangular cross-section is usually used; for n equal to 3 (120 °), 5 (72 °) or 6 (60 °) one is usually (for n a cuvette with a circular cross-section can of course also be used equal to 2 or 4. The combination of excitation and detection of the n markers Mμ can be carried out both simultaneously and in succession using the arrangements mentioned. 31

II.2) A1 / D.A2 / D, ..., An-l / D, An / D (the n markers Mμ are each excited by their corresponding unit Aμ and detected with a detection unit D, e.g. a multi-wavelength detector.

a) The arrangement of the units Aμ can be designed in accordance with the explanations given under II.1). If the units Aμ are arranged in a row (case ai), the unit D can be installed in a fixed position in the corresponding χ position if the radiation entrance window is of sufficient size or if appropriate imaging optics are used. Otherwise (case a ₂ ), a (translational) tracking must take place in the corresponding position. In the case of the other arrangements of the units Aμ (case a ₃ ), a (translational and rotary) adjustment of the unit D into the corresponding χ positions must take place. Thus, in case ai, the combination of excitation and detection of the n markers Mμ can take place both simultaneously and in succession, in cases a ₂ and a ₃ only in succession.

b) In principle, an arrangement based on b) under point 1.3) is possible, i.e. the optical axis of the unit D is parallel to the longitudinal axis of a cylindrical sample cell, the units Aμ are arranged in accordance with the explanations given under II.1). However, this results in different path lengths which the fluorescent radiation emitted by the respective marking substances Mμ must travel through the sample on the way to unit D, or different solid angles at which the fluorescent radiation hits unit D (or its detection window). This can lead to inaccuracies in the detected intensities or must be taken into account accordingly in the evaluations. In principle, however, the combination of excitation and detection of the n marking substances Mμ can be carried out both simultaneously and in succession in these arrangements.

II.3) Al / D (l, 2, ..., nl, n), A2 / D (1, 2, ..., nl, n), ..., An-1 / D (l, 2, ..., nl, n), An / D (l, 2, ..., nl, n) (the n markers Mμ are each excited and detected by their corresponding unit Aμ).

a) The instructions essentially correspond to those set out in a) under point II.2). Instead of a unit D (eg a multi-wavelength detector), however, a detection unit is used which, for example (case ai), contains exchangeable photodetectors and / or exchangeable optical filters (and possibly polarizers) δiμ. Furthermore, D can also contain several photodetectors δiμ, which the respective emitted 32

Fluorescence radiation, for example (case a ₂ ) by means of optical fibers or optical fiber bundles, is supplied. With a unit D corresponding to case ai, the combination of excitation and detection ^'of the n markers m.mu. only take place sequentially, as a change of the subunits must be δiμ and possibly also a (translational or translational and rotational) readjustment of the unit D. With a unit D corresponding to case a ₂ , the combination of excitation and detection of the n marking substances Mμ can be carried out in succession and potentially (with a suitable arrangement of the units Aμ), if, for example, by means of suitable optical devices, bundling (for example by optical lens) of the fluorescent radiation emitted by the marking substances Mμ onto the optical fibers or fiber bundles.

b) The instructions essentially correspond to those set out in b) under point II.2). Instead of a unit D (for example a multi-wavelength detector), however, a detection unit is used which, for example (case ai), contains interchangeable photo detectors and / or interchangeable optical filters (and possibly polarizers) δiμ. Furthermore, D can also contain a plurality of photodetectors δiμ, to which the respective emitted fluorescent radiation, for example (case a ₂ ), is fed by means of optical fibers or optical fiber bundles. With a unit D corresponding to case ai, the combination of excitation and detection of the n marking substances Mμ can only take place in succession. With a unit D corresponding to case a ₂ , the combination of excitation and detection of the n markers Mμ can be carried out in succession and potentially also simultaneously. The explanations in b) under point II.2) regarding the different path lengths and solid angles of the fluorescence radiation emitted by the marking substances Mμ naturally also apply here.

II.4) A1 / A2 /.../ An-1 / An / Dl / D2 /.../ Dn-l / Dn (the n markers are excited or detected simultaneously by their corresponding units Aμ or Dμ) .

The simultaneous excitation or detection of the n marking substances can in principle be carried out with the arrangements and geometric relationships as described in point II.1), point II.2) in case ai of a), point II.2) in b ), Point II.3) in case a ₂ of a) and point II.3) in case a ₂ of b). 33

The arrangements and exemplary construction options of detection devices in case I, i.e. when excited in the same sample volumes, they are generally suitable for successively exciting the n markers Mμ.

The arrangements and exemplary construction options of detection devices in case II, i.e. with excitation in different sample volumes, are usually suitable for the simultaneous excitation of all n markers Mμ. Such arrangements and exemplary construction options for detection devices are particularly suitable, in which the fluorescence radiation emitted in each case can also be detected simultaneously at spatially different locations.

In general, the excitation radiation of the units Aμ can be pulsed or continuous, i.e. in continous wave (CW) mode. Furthermore, the intensity of the excitation radiation of each unit Aμ can be modulated with a frequency fμ, so that this unit Aμ excites fluorescence radiation of the marking substance Mμ which is also intensity-modulated with fμ and which can be selectively measured by Dμ. Usually, modulation frequencies are used which differ from the frequency of the power grid (usually 50 Hz) and the half and integer multiples of this frequency. In the case of simultaneous excitation and detection of the fluorescence radiation emitted by all the markers Mμ, the different modulation frequencies fμ allow the fluorescence radiation of the respective markers Mμ to be assigned and a better signal / noise ratio to be achieved. The "lock-in method" is usually used to detect the intensity-modulated fluorescence signals.

A preferred embodiment of the method according to the invention for the detection of marking substances in liquids which have been marked according to the method according to the invention consists in the successive excitation of the n marking substances Mμ by their corresponding units Aμ in the same sample volume and the (temporally successive) Detection of the fluorescence radiation emitted by Mμ.

A further preferred embodiment of the method according to the invention for the detection of marking substances in liquids which have been marked according to the method according to the invention consists in the simultaneous excitation of the n marking substances Mμ by their corresponding units Aμ in the same sample volume and simultaneously or in succession 34 detection of the fluorescence radiation emitted by Mμ in each case by means of a multi-wavelength detector.

A further preferred embodiment of the method according to the invention for the detection of marking substances in liquids which have been marked according to the method according to the invention consists in the simultaneous excitation of the n marking substances Mμ by a polychromatic unit A in the same sample volume and the simultaneous or temporally successive one Detection of those emitted by Mμ

Fluorescence radiation using a multi-wavelength detector.

A further preferred embodiment of the method according to the invention for the detection of marking substances in liquids which have been marked according to the method according to the invention consists in the simultaneous excitation of the n marking substances Mμ by respective units Aμ with the frequency fμ intensity-modulated in the same sample volume and the simultaneous or sequential detection of the respective fluorescence radiation emitted by Mμ and intensity-modulated.

A further preferred embodiment of the method according to the invention for the detection of marking substances in liquids which have been marked according to the method according to the invention consists in the simultaneous excitation of the n marking substances Mμ by their corresponding units Aμ in different sample volumes and that in succession or at the same time detection of the fluorescence radiation emitted by Mμ by means of the respective unit Dμ.

Preferably used in the units Aμ as radiation sources αiμ semiconductor lasers, semiconductor diodes or solid-state lasers, which have a maximum emission in the spectral range from λ _ma χ - 100 nm to λ _max + 20 nm, where λ _ma x denotes the wavelength of the absorption maximum of the respective marking substance Mμ .

Semiconductor detectors, in particular silicon photodiodes or germanium photodiodes, are advantageously used as the photodetectors δiμ in the units Dμ.

Interference filters and / or edge filters with a short-wave transmission edge in the range from m _ax to λ _max + 80 nm are preferred as optical filters in the photo detectors δiμ of the units Dμ, where λ _max denotes the wavelength of the absorption maximum of the respective marking substance Mμ. 35

If necessary, one or more NIR polarizers can also be used.

The following example is intended to explain the invention in more detail.

Example 1:

A mixture of 0.5 pp A (PcH- (3'-methylphenyloxy)), B (PcH ₂ - (cyclopentylamino)) and C (NcH ₂ - (OCH ₉ ) ₈ ) is made in unleaded petrol (RON 95 ) solved (PcH ₂ denotes that

Phthalocyanine system in which Me ¹ (formula Ia) twice hydrogen and one residue of the pairs R ¹ and R ⁴ , R ⁵ and R ⁸ , R ⁹ and R ¹² and R ¹³ and R ¹⁶ in formula Ia hydrogen, the other Residue corresponds to 3'-methylphenyloxy (A) or cyclopentylamino (B); NcH denotes the naphthalocyanine system in which Me ² (formula II) corresponds twice to hydrogen, and all pairs of residues Y ¹ and Y ² , Y ³ and Y ⁴ , Y ⁵ and Y ⁶ as well as Y ⁷ and Y ⁸ in formula II OC ₄ H ₉ (C) correspond).

The absorption spectrum of the mixture of markers from A, B and C shows essentially no overlap of the absorption spectra of the individual markers.

Claims

36 Patent claims

1. A method for marking liquids with at least two markers, characterized in that the markers

have substantially non-overlapping absorption areas and

at least one of the marking substances has a wavelength of the absorption maximum of more than 850 nm.

2. The method according to claim 1, characterized in that markers are used whose respective wavelength of the absorption maximum is in the spectral range from 600 to 1200 nm.

3. Process according to claims 1 or 2, characterized in that n markers are added, where n is an integer from 2 to 10.

4. Process according to claims 1 or 2, characterized in that n markers are added, where n is an integer from 2 to 6.

5. The method according to claims 1 or 2, characterized in that n markers are added, where n is an integer from 2 to 4.

6. Process according to claims 1 to 5, characterized in that compounds are added as markers which are selected from the group consisting of metal-free and metal-containing phthalocyanines, metal-free and metal-containing naphthalocyanines, nickel-dithiolene complexes, aminium compounds of aromatic amines , Methine dyes, square acid dyes and crocodic acid dyes.

7. The method according to claims 1 to 6, characterized in that at least one compound selected from the group consisting of metal-free and metal-containing naphthalocyanines, nickel-dithiolene complexes, aminium compounds as markers with a wavelength of the absorption maximum of more than 850 nm of aromatic amines, methine dye - 37 fen, square acid dyes and crocodic acid dyes added.

.. Method for the detection of markers in liquids which have been marked according to a method according to claims 1 to 7, characterized in that one uses a radiation source which emits radiation in the absorption areas of all markers, and one the fluorescent radiation emitted by the markers proves.

9. A method for the detection of marking substances in liquids which have been marked according to a method according to claims 1 to 7, characterized in that for each marking substance a corresponding radiation source is used which is in the absorption region of the marking substance

Radiation is emitted, and the fluorescent radiation emitted by the markers is detected.

10. The method according to claim 9, characterized in that the radiation sources are semiconductor lasers, semiconductor diodes or

Solid-state lasers are used which have a maximum emission in the spectral range from λ- _nax -100 nm to λm _ax + 20 nm, where λ _max denotes the wavelength of the absorption maximum of the corresponding marker.

11. Liquids which have been labeled according to a method according to claims 1 to 7.