Analyses on condom evidence: Condom brand profiling via HS-SPME-GC-MS and temperature-brand effect on condom fingerprint development

Date

2018-12

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Abstract

Condoms are a challenging substrate as an evidentiary item since they do not hold a determined shape and fundamental composition may vary depending on the brand. Developmental variables in regard to condoms substrates were investigated to optimize latent print methodologies. Fingerprints were deposited onto condoms of various brands, exposed to different temperatures, and developed with superglue fuming, magnetic powder, and Rhodamine 6G (R6G). For magnetic powder, results indicated that the highest average fingerprint score was obtained on condoms stored in 15°C temperatures. With R6G, the average fingerprint score was higher for Durex brand condoms processed at an elevated temperature of 40°C. Fingerprint development scores were the lowest on Crown brand condoms, but out of all the tested brands, development with R6G after stored in cool temperature had the highest average score. These differences indicate that optimal fingerprint development is achieved by using the method that regards substrate and environment conditions. As indicated by differences in fingerprint development on different brands of condoms, brand details can be relative information not only as an artifact of information to a case but as a variable of analytical interest when applying forensic methodologies to these substrates. To make condom brand profiling more practical, methods that involve relatively fewer procedural steps and less manipulation of the sample should be evaluated. Condoms were sampled using a simple sampling procedure, solid phase microextraction (SPME), and analyzed using gas chromatography-mass spectrometry (GC-MS). Sampling conditions were tested by sampling a single brand of condoms with various SPME fibers: PA, PDMS, DVB/PDMS, CAR/PDMS, and DVB/CAR/PDMS - and different sampling times: 1 hr., 3 hrs., 6 hrs., 12 hrs., and 24 hrs. Other sampling conditions including exposure to temperatures, 35ºC and 70ºC, were also tested. DVB/CAR/PDMS at 12 hrs. was the sampling condition that achieved the greatest number of unique compounds with the least sampling time. Using these sampling conditions, condom brands, Durex, LifeStyles, and Crown were sampled. Using principle component analysis and hierarchical clustering with the chemical profile of each sample, the brands were able to be discriminated.

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Keywords

Latent Fingerprints, Development, Condoms, Solid-phase Microextraction, Brands, Discriminate

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