HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS WITH FLUORESCENCE DETECTION OF ETHYL CENTRALITE AND 2,4-DINITROTOLUENE IN GUNSHOT RESIDUESAFTER DERIVATIZATION WITH 9-FLUORENYLMETHYLCHLOROFORMATE

A reversed-phase high-performance liquid chromatographic method using 9-fluorenylmethylchloroformate (FMOC) as fluorogenic labeling reagent for the detection of ethyl centralite (EC) and 2,4-dinitrotoluene (2,4 -DNT) in gunshot residues is reported. Residues were sampled with cott on wool swabs which were then extracted and the extracts cleaned by TL C. The sample spots on the TLC plate were scraped off and extracted to recover the analytes. The extract corresponding to EC was hydrolyzed while 2,4-DNT was reduced. The hydrolysis and reduction products (N-et hylaniline and 2,4-diaminotoluene, respectively) were derivatized with FMOC in alkaline buffer solution at 52 degrees C for 20 min. The deri vatives were analyzed by a reversed-phase HPLC with fluorescence detec tion. The detection limits for EC and 2,4-DNT were 200 pg and 1 ng per standard sample, respectively. Three out of eleven kinds of gunpowder s analyzed were found to contain EC, while another three were found to contain 2,4-DNT. According to the results of gunpowder analysis, two different kinds of ammunition, which were presumed to contain EC in on e and 2,4-DNT in the other, were chosen for test firings. Ethyl centra lite was detected in cotton swabs sampled from spent cartridge cases o f both of these two kinds of ammunition, but 2,4-DNT was not detected in any of these spent cases. Nine out of twelve samples swabbed from s hooting hands at various times after firing two rounds of either kind of ammunition were found to contain EC, while none of these swabs were found to contain 2,4-DNT. The quantities of EC recovered from these h and swabs were shown to be in the range of 0.6 to 4.0 ng.