Philp, M. & Fu, S. 2018, 'A review of chemical 'spot' tests: A presumptive illicit drug identification technique.', Drug Testing and Analysis, vol. 10, no. 1, pp. 95-108.View/Download from: UTS OPUS or Publisher's site
Chemical 'spot' tests are a presumptive illicit drug identification technique commonly used by law enforcement, border security personnel, and forensic laboratories. The simplicity, low cost, and rapid results afforded by these tests make them particularly attractive for presumptive identification globally. In this paper, we review the development of these long-established methods and discuss color test recommendations and guidelines. A search of the scientific literature revealed the chemical reactions occurring in many color tests are either not actively investigated or reported as unknown. Today, color tests face many challenges, from the appearance of new psychoactive substances to concerns regarding selectivity, sensitivity, and safety. Advances in technology have seen color test reagents used in digital image color analysis, solid sensors, and microfluidic devices for illicit drug detection. This summarizes current research and suggests the future of presumptive color testing.
Philp, M., Shimmon, R., Tahtouh, M. & Fu, S. 2018, 'Color Spot Test As a Presumptive Tool for the Rapid Detection of Synthetic Cathinones.', Journal of visualized experiments : JoVE, no. 132.View/Download from: Publisher's site
Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and other border protection agencies globally. Color testing is a presumptive identification technique indicating the presence or absence of a particular drug class using rapid and uncomplicated chemical methods. Owing to their relatively recent emergence, a color test for the specific identification of synthetic cathinones is not currently available. In this study, we introduce a protocol for the presumptive identification of synthetic cathinones, employing three aqueous reagent solutions: copper(II) nitrate, 2,9-dimethyl-1,10-phenanthroline (neocuproine) and sodium acetate. Small pin-head sized amounts (approximately 0.1-0.2 mg) of the suspected drugs are added to the wells of a porcelain spot plate, and each reagent is then added dropwise sequentially before heating on a hotplate. A color change from very light blue to yellow-orange after 10 min indicates the likely presence of synthetic cathinones. The highly stable and specific test reagent has the potential for use in the presumptive screening of unknown samples for synthetic cathinones in a forensic laboratory. However, the nuisance of an added heating step for the color change result limits the test to laboratory application and decreases the likelihood of an easy translation to field testing.
Philp, M., Shimmon, R., Tahtouh, M. & Fu, S. 2016, 'Development and validation of a presumptive color spot test method for the detection of synthetic cathinones in seized illicit materials', Forensic Chemistry, vol. 1, pp. 39-50.View/Download from: Publisher's site
© 2016 Elsevier B.V. Significant quantities of unknown, potentially illicit substances are seized by law enforcement and border protection agencies annually. Color testing is an ideal presumptive test and is commonly employed to provide rapid, selective, inexpensive and simple analyses. Synthetic cathinones are a class of psychoactive substances that do not currently have a suitable, specific color test regularly employed for presumptive identification. Herein, we report on the development and validation of a presumptive color test method employing test reagent, copper(II)-2,9-dimethyl-1,10-phenanthroline (Cu(II)-neocuproine). The procedure is based on the reduction of copper(II) to copper(I) in the presence of the drug, followed by formation of a yellow-orange colored complex with maximum absorbance at 453 nm. The simple spot test elicited a positive result for 39 out of 44 cathinone substances tested, which gave a false negative response rate slightly greater than 10%. The structural complexity of cathinone substances, as determined by fractional sp 3 (Fsp 3 ) values, were able to classify those that failed to react. Other recreational drugs, adulterants and white powders tested afforded a yellow color change in 10 out of 83 substances examined; however, most of these were still distinguishable from a true positive test result. The color test was applied to cathinone samples cut with glucose and caffeine down to 5% g/g purity, as well as commonly found mixtures of synthetic cathinones, with no effect on the positive color change. The highly stable Cu(II)-neocuproine test reagent has potential for use in preliminary screening of unknown samples for cathinones in forensic laboratory testing.
Wenholz, D.S., Luong, S., Philp, M., Forbes, S.L., Stuart, B.H., Drummer, O.H. & Fu, S. 2016, 'A study to model the post-mortem stability of 4-MMC, MDMA and BZP in putrefying remains', FORENSIC SCIENCE INTERNATIONAL, vol. 265, pp. 54-60.View/Download from: UTS OPUS or Publisher's site
Philp, M., Shimmon, R., Stojanovska, N., Tahtouh, M. & Fu, S. 2013, 'Development and validation of a presumptive colour spot test method for the detection of piperazine analogues in seized illicit materials', Analytical Methods, vol. 5, no. 20, pp. 5402-5410.View/Download from: UTS OPUS or Publisher's site
The increasingly large quantities of potentially illicit samples received for confirmatory analysis highlights the importance and demand for preliminary testing procedures that are simple, rapid, selective, inexpensive and able to be used in the field. C