Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/72—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving blood pigments, e.g. haemoglobin, bilirubin or other porphyrins; involving occult blood
  • G01N33/728—Bilirubin; including biliverdin
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S436/00—Chemistry: analytical and immunological testing
  • Y10S436/903—Diazo reactions
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T436/00—Chemistry: analytical and immunological testing
  • Y10T436/14—Heterocyclic carbon compound [i.e., O, S, N, Se, Te, as only ring hetero atom]
  • Y10T436/145555—Hetero-N
  • Y10T436/146666—Bile pigment

Definitions

• ABSTRACT Bilirubin particularly as contained in body fluids, is determined with test strips comprising an absorbent wherein X is a stabilizing anion; R and R which may be the same or different, are
• halogen or lower alkyl or alkoxy and R and R which may be the same or different, are hydrogen, halogen, nitro, or lower alkyl or alkoxy; the aromatic ring in formula (1) containing either (a) 1 to 3 halogen atoms or (b) one nitro group, but not both together; and an amount of an acid sufficient for a coupling reaction between bilirubin and said diazonium salt.
• German Pat. No. 1,102,444 describes a reagent tablet containing a diazonium salt and a strong acid which is placed on a spot plate moistened with a body fluid and, after moistening with water, makes the bilirubin visible as a violet ring on the substrate.
• test papers these are absorbent carriers which have been impregnated with all the reagents necessary for the detection reaction.
• German Pat. No. 2,007,013 it is known from German Pat. No. 2,007,013 to use test papers which contain certain 2,4- and 2,5- disubstituted diazonium salts for the detection of bilirubin in serum and urine.
• this method is relatively insensitive and, according to our investigations, also suffers from certain disadvantages with regard to the speed of the reaction and the sensitivity, which lessens its practical utility.
• the possibility of increasing the sensitivity of the detection reaction but, in this case, new difficulties arise.
• the urobilinogen which is also present in urine also reacts in the presence of these activators and simulates an increased biliburin content.
• the normal disturbing reactions with components of the urine are hereby also activated, which can manifest themselves as false colorations or even give falsely positive indications.
• these diazonium salts can be used to prepare test strips which react selectively with bilirubin not only in urine but also in serum.
• the diazonium salts used in this invention are of the formula:
• R and R which may be the same or different, are
• aromatic ring in formula (I) may contain either (a) l to 3 halogen atoms or (b) one nitro group, but not both together.
• the diazonium salts of general formula (I) are either known or can be prepared from known aromatic amines by diazotization.
• the lower alkyl or alkoxy radicals in the diazonium salts (I) are to be understood to contain up to 3 carbon atoms each.
• the diazonium salts (I) are preferably used in the form of the fluoborates (i.e., wherein X is a fluoborate anion), the stability of which is known; however, other stable salts, such as aryl-sulfonates, especially naphthalene-1,5-disulfonates, can also be used.
• Diazonium salts of general formula (I) are preferred in which R and R are both halogen atoms, especially chlorine or bromine atoms, and the other symbols stand for hydrogen atoms.
• activators there can be used, apart from anionic wetting agents, especially compounds of the general formula:
• R and R which may be the same or different, are unsubstituted or substituted aliphatic, cycloaliphatic, araliphatic or aromatic radicals.
• the radicals R and R are preferably identical since phosphoric acid diesters of this type are particularly simple to prepare.
• the aliphatic radicals R and R can be straightchained or branched and can contain up to 18 carbon atoms, the effectiveness of the esters initially increasing with an increasing number of carbon atoms but beyond a chain length of about 14 carbon atoms, the effectiveness again decreases due to the increasingly hydrophobic character of the esters.
• cycloalkyl radicals those with 5-8 carbon atoms are especially preferred.
• Preferred substituents in the aliphatic and cycloaliphatic radicals include, for example, halogen atoms, especially chlorine and bromine atoms, nitro groups and alkoxy radicals containing up to 8 carbon atoms.
• phosphoric acid diesters of general formula (II) are preferred in which R and R both represent aromatic radicals.
• Preferred aromatic radicals include monoand polynuclear, unsubstituted and substituted aryl radicals, for example, phenyl, xylyl, tolyl, chlorophenyl, nitrophenyl and naphthyl radicals.
• araliphatic radicals there are preferably used, for example, phenyl or naphthyl radicals which are connected to the phosphoric acid residue via an alkylene bridge containing up to 3 carbon atoms.
• an absorbent carrier preferably filter paper
• a solution which contains 0.0 l-2.0 g., preferably 0.050.5 g., per 100 ml. of a diazonium salt of general formula (I), as well as 3-20 g., preferably 5-15 g., per 100 ml. of a phosphoric acid diester of general formula (II) and 230 g. of a solid inorganic or organic acid and thereafter dried.
• a solution which contains 0.0 l-2.0 g., preferably 0.050.5 g., per 100 ml. of a diazonium salt of general formula (I), as well as 3-20 g., preferably 5-15 g., per 100 ml. of a phosphoric acid diester of general formula (II) and 230 g. of a solid inorganic or organic acid and thereafter dried.
• v diazotization in the impregnation solution or on the absorbent carrier.
• an appropriate amine is used as starting material which is
• the bilirubin test strips according to the present invention can also contain stabilizing agents for the diazonium salts, for example sodium fluoborate, magnesium sulfate, sodium metaphosphate, aryl-sulfonates or the like.
• test strips can also contain wetting agents in order to improve the absorbency of the test papers.
• wetting agents can be used which are still surface-active in the strongly acidic medium after dipping into a body fluid to be tested, for example cationic agents (e.g. lauryl-pyridinium chloride), non-ionic agents (e.g. polyoxyethylene triglyceride) and anionic agents, especially the sulfonates and sulfates (e.g. dodecyl-benzene-sulfonate).
• cationic agents e.g. lauryl-pyridinium chloride
• non-ionic agents e.g. polyoxyethylene triglyceride
• anionic agents especially the sulfonates and sulfates (e.g. dodecyl-benzene-sulfonate).
• the latter can additionally possess activating properties.
• the wetting agents can be used in the impregnation solution in concentrations of O. l2% and preferably of 0.2-0.5%.
• solvents or solvent mixtures for the impregnation there can be used all those which do not react with the diazonium salts, in which all the components are soluble and which have a low boiling point in order that, upon drying, the diazonium salts are not subjected to too high a temperature. It has also proved to be advantageous to impregnate individual components in separated working steps.
• a mixture of a diazonium salt (I) and an acid, for example metaphosphoric acid can first be used for impregnation from an aqueous solution and then a further impregnation is carried out with a solution of a phosphoric acid diester (II) in ethyl acetate or chloroform.
• absorbent carrier it is preferred to use filter paper but other absorbent carriers, for example, glass fiber paper and synthetic fiber fabrics and fleeces made from acid-resistant fibers, such as polyester and polypropylene fibers, can also be used.
• acid-resistant fibers such as polyester and polypropylene fibers
• test paper used herein is to be understood to include these materials.
• the present invention provides a test strip for the detection of bilirubin in body fluids, which comprises an absorbent carrier containing at least one diazonium salt of general formula (I) and an amount of an acid sufficient for the coupling reaction.
• Phosphoric acids of general formula (II) are known (see, for example, l-Iouben-Weyl, Methoden d. Org. Chem., Vol. XII/2, pp 226 et seq.). Since the compounds (II) themselves have an acidic reaction, they can at least partially replace the acid needed for the coupling reaction. However, additional amounts of acid are usually necessary. For this purpose, a whole series of solid acids can be used. Of particular use are, for example, oxalic acid, citric acid, potassium bisulfate and, especially having regard to the stability of the diazonium salt, commercially available metaphosphoric acid, which can contain up to about of its sodium salt.
• test strips according to the present invention react with bilirubin-containing urine in about 5 to 30 seconds to give red to blue color shades. With normal urine, there is obtained a yellow reaction color. Urobilinogen reacts, without disturbing, with a yellow color, red shades only occurring when unusually large amounts thereof are present in the urine (more than about 8-10 mg.%).
• the detection of serum bilirubin is, of course, also possible with the use of the test strips according to the present invention.
• the impregnated absorbent carriers can be cut up into long strips and then rolled up so that, when needed, a small piece can be torn or cut off. They can also be cut up into small rectangles and stuck or sealed on to one end of narrow strips of synthetic resins. It is of particular advantage when the test papers are sealed between two synthetic resin films according to the method described in German Patent No. l,546,307 or between a synthetic resin film and a meshwork as described in German Patent No. 2,1 18,455, because there is then no danger that the reagents will be washed out upon dipping into a body fluid.
• Test papers which contain 2,6-dib'romobenzenediazonium fluoborate reacted in an analogous manner.
• phosphoric acid di-o-tolyl-ester phosphoric acid di-p-tolyl ester; phosphoric acid bis-3,5-xylol ester; phosphoric acid bis-o-chlorophenyl ester; phosphoric acid bis-p-chlorophenyl ester; phosphoric acid bis-p-nitrophenyl ester; phosphoric acid dicyclohexyl ester; or phosphoric acid dipentyl ester.
• 2,6-dichlorobcnzcne-diazonium fluoborate 0.16 g. metaphosphoric acid 15.0 g. dodecyl-benzene-sulfonic acid sodium salt 1.0 g. methanol 20.0 ml. distilled water ad 100.0 ml.
• test paper of the same composition except that it contained 2,4-dichlorobenzene-diazonium fluoborate, reacted with bilirubin with a blue-violet color and, with urobilinogen-containing urine, a disturbing violet coloration occurred after only a short period of time.
• This paper was then impregnated with a 5% solution of phosphoric acid diphenyl ester in ethyl acetate.
• This test paper was thereafter impregnated with a 10% solution of phosphoric acid diphenyl ester in ethyl acetate and dried at 40C.
• Analogous test papers could be prepared with an equimolar amount of one of the following substituted aniline derivatives: 2,6-dimethyl-3-bromoaniline; 2,6-dimethyl-4-bromoanilinei 2,6-dimethoxy-3- bromoaniline; and 2,6-dimethoxy-4-chloroaniline.
• test papers obtained correspond approximately to those of the test papers according to Examples 1 and 4.
• This paper was subsequently impregnated with a 10% solution of commercially available isooctyl-phosphoric, acid in methylene chloride.
• This acid is a mixture of about 55% of the diester and 45% of the monoester of phosphoric acid with isomeric C alcohols.
• Test strip as claimed in claim 1, wherein said dia-- zonium salt is 2,6-dichlorobenzene-diazonium fluoborate.
• Test strip as claimed in claim 1, wherein said diazonium salt is 2-methoxy-4,6-dibromobenzenediazonium fluoborate.
• test strip as claimed in claim 1, wherein said diazonium salt is 2,4,6-trichlorobenzene-diazonium toluenesulfonate.
• Test strip as claimed in claim 1 also containing an activator.
• R and R are unsubstituted or substituted aliphatic, cycloaliphatic, araliphatic or aromatic radicals.
• Test strip as claimed in claim 1 wherein the absorbent carrier is impregnated with a solution containing, per ml., 0.0l2.0 g. of the diazonium salt, 3-20 g. of the phosphoric acid diester and 2-30 g. of a solid inorganic or organic acid.
• Test strip as claimed in claim 1 also containing a stabilizing agent.
• Test strip as claimed in claim 1 wherein said absorbent carrier is sealed between a synthetic resin film and a meshwork.
• Method for detecting bilirubin in body fluids which method comprises contacting a test sample suspected of containing bilirubin with a test strip as claimed in claim 1.

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Citations (6)

• 1972
  • 1972-08-17 DE DE2240471A patent/DE2240471C3/de not_active Expired
• 1973
  • 1973-07-24 US US382241A patent/US3880588A/en not_active Expired - Lifetime
  • 1973-08-13 FR FR7329503A patent/FR2196717A5/fr not_active Expired
  • 1973-08-14 GB GB3843073A patent/GB1389368A/en not_active Expired
  • 1973-08-14 CH CH1170273A patent/CH572213A5/xx not_active IP Right Cessation
  • 1973-08-16 AT AT715273A patent/AT326277B/de active
  • 1973-08-17 JP JP48092331A patent/JPS5759497B2/ja not_active Expired
• 1978
  • 1978-02-16 BE BE185234A patent/BE864030Q/xx not_active IP Right Cessation
  • 1978-03-14 KE KE2830A patent/KE2830A/xx unknown
  • 1978-03-23 HK HK163/78A patent/HK16378A/xx unknown

Patent Citations (6)

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