Chemistry: analytical and immunological testing – Peptide – protein or amino acid – Amino acid or sequencing procedure
Patent
1991-05-24
1993-06-22
Housel, James C.
Chemistry: analytical and immunological testing
Peptide, protein or amino acid
Amino acid or sequencing procedure
436112, 436113, 436164, 436172, G01N 3368
Patent
active
052216276
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a method for the detection and or quantitation of .alpha.-amino acids in chemical and biochemical analyses and particularly but not exclusively to a method for the detection of latent fingerprints.
At present a common method of detection of amino acids comprises applying ninhydrin (1,2,3-triketohydrindene hydrate) to the amino acid. The ninhydrin reacts with the amino acid on heating yielding a purple colouration.
As amino acids are secreted from human finger tips, ninhydrin is often used in the detection of latent fingerprints, in, for example, criminal investigation.
We have discovered an alternative group of compounds which can be used for this purpose.
According to the present invention there is provided a method of detection of amino acids comprising the application, to the material being tested, of a reagent comprising the following basic formula: ##STR2## wherein X, Y and/or Z may be nitrogen, C--H, C-alkyl or C-aryl and wherein A, B, C and/or D may be an alkyl or aryl substituent either alone or in combination.
In a preferred embodiment of the invention the substituents X, Y, Z, A, B, C and D are one of the following combinations
In order that the invention may be more readily understood, a specific embodiment thereof will now be described by way of example:
A method of detecting amino acids comprises the addition to the material being tested of a compound comprising the following basic structure ##STR3## wherein X, Y and Z may be nitrogen, C--H, C-alkyl or C-aryl and A, B, C and D may be alkyl, aryl alkyl or aryl substituent either alone or in combination.
Some preferred examples of the compound used in the method are as follows: ##STR4##
Many substituents of functional groups are possible. Each ring could be variously substituted, for example, with alkyl and aryl substituents.
The compounds of the method of the invention may be synthesized by a variety of methods. One such method of producing such a compound is disclosed in Helv.Chim.Acta., 1950, 50, 1080, which reveals a method of synthesising 1,8-Diazafluoren-9-one (1). Other compounds of the invention could be produced, for example, by appropriate substitution reactions of 1,8-Diazofluoren-9-one of (1).
In practice the compound (I) is dissolved in a suitable solvent system such as methanol/acetic acid/trichlorotrifluorethane so as the concentration of the reagent (I) solution is in the range from substantially 0.05 to 2%.
The document or sample containing or supporting the amino acid such as a latent fingerprint is immersed in the reagent (I) solution. The amino acid sample may be subsequently be removed from the reagent (I) solution after a suitable time period has elapsed, for example approximately five seconds. The sample is then allowed to dry. Drying should be complete after approximately thirty seconds. The sample is then re-immersed in the reagent (I) solution for example for thirty seconds. The sample is subsequently removed from the reagent (I) solution and the amino acids may then be developed by, for example, heating the sample at 110.degree. C. for ten minutes.
The reagent (I) in combination with the amino acid produces coloured fluorescent species with .lambda. (excitation) in the order of 470 nm and (emission) in the order of 570 nm on paper. The fluorescent fingerprints can be made visible by using blue/green light for excitation and observing the light emission through a filter such as a 610 nm filter.
The invention will now be further illustrated by the following examples.
EXAMPLE 1
1,8-Diazafluoren-9-one (1) (0.05 g) was dissolved in a mixture of methanol (4 ml) and acetic acid (2 ml) and was then diluted up to 100 ml with trichlorotrifluoroethane (Fluorosil) so as to form a reagent (1) solution. A sheet of paper on which a latent fingerprint was situated, was immersed in the reagent (1) solution for 5 seconds. The paper was removed from the reagent (1) solution and allowed to dry for 30 seconds. The paper was then immersed for a further five seconds and was subsequently removed from the reagent (
REFERENCES:
Wittman, H. et al. "New reagents for the detection of amino acids by paper chromatography," Monatsh. Chem., 101(5), 1388-1393, 1970.
Grigg Ronald E.
Mongkolaussavaratana Teirevat
Pounds Charles A.
Housel James C.
Redding David
The Queen's University of Belfast
Tolpin Thomas W.
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