NCJ Number
51801
Journal
Journal of Forensic Sciences Volume: 23 Issue: 4 Dated: (OCTOBER 1978) Pages: 852-855
Date Published
1978
Length
4 pages
Annotation
EXPERIMENTS INVOLVING 1,000 LATENT FINGERPRINTS ON A TYPE OF COMMONLY-USED WHITE PAPER SHOW NINHYDRIN IS THE MORE VERSATILE REAGENT BUT 4-DIMETHYLAMINO-CINNAMALDEHYDE (DMAC) CAN BE USED UNDER CERTAIN CONDITIONS.
Abstract
THIS REPORT IS THE FIRST PART OF A COMPREHENSIVE RESEARCH PROGRAM BEING CONDUCTED IN COOPERATION WITH THE ISRAEL POLICE DEPARTMENT, TO FIND REAGENTS TO REPLACE NINHYDRIN FOR THE DEVELOPMENT OF LATENT FINGERPRINTS. THE NINHYDRIN METHOD IS SLOW, REQUIRES HEAT FOR COMPLETE DEVELOPMENT, AND IS SOMETIMES MISLEADING BECAUSE NOT ALL INDIVIDUALS EXCRETE SUFFICIENT PERSPIRATION TO LEAVE LATENT PRINTS IDENTIFIABLE WITH NINHYDRIN. THE EXPERIMENTS WITH DMAC ANALYZING 1,000 FINGERPRINGS FROM 100 INDIVIDUALS ARE DESCRIBED. A TABLE PRESENTS THE LABORATORY DATA. THE DMAC REAGENT WAS PREPARED IN VARIOUS STRENGTHS USING VARYING CONCENTRATIONS OF ACIDS. THIS WAS THEN SPRAYED ON THE PRINT-BEARING PAPER OR THE PAPER WAS DIPPED IN THE REAGENT. IT WAS FOUND THAT ALL THE DMAC FORMULATIONS RESULTED IN BACKGROUND COLORATION WHICH COULD BE REDUCED BY KEEPING THE FRESHLY DEVELOPED PRINTS IN THE DARK FOR A FEW DAYS. THE BEST FORMULATIONS USED EITHER 4-PHENOLSULFONIC OR SULFOSALICYLIC ACID COMBINED WITH THE DMAC IN AN ETHYL-ALCOHOL MEDIUM. SUCH A SOLUTION CAN BE STORED IN AN OPAQUE AEROSOL SPRAYER AT ROOM TEMPERATURE FOR AT LEAST A FEW MONTHS WITHOUT NOTICEABLE DETERIORATION. WHILE NINHYDRIN CAN DEVELOP PRINTS THAT ARE SEVERAL MONTHS OLD, DMAC PROVED INEFFECTIVE ON PRINTS MORE THEN 72 HOURS OLD BECAUSE THE UREA IN THE PRINTS, WHICH IS ESSENTIAL TO THE DMAC REACTION, DIFFUSES AND DECOMPOSES RAPIDLY. THESE STUDIES SHOW NINHYDRIN IS THE MORE VERSITILE REAGENT BUT THAT DMAC CAN BE USED FOR THE QUICK DEVELOPMENT OF FRESH PRINTS WHEN THE APPLICATION OF HEAT IS FORBIDDEN OR IMPOSSIBLE (SUCH AS PRINTS ON PAPER USED TO WRAP AN EXPLOSIVE). REFERENCES ARE INCLUDED. (GLR)