Stability and Detectability of Lachrymators and Their Degradation Products in Evidence Samples

The detectability and stability of lachrymators [2-chloroacetophenone (CN), o-chlorobenzylidene malononitrile (CS) and synthetic capsaicin (nonivamide)] were investigated using dichloromethane extraction followed by gas chromatography-mass spectrometry. Ultrasonication at 40°C slightly improved the extraction yields of nonivamide to almost quantitative yield, compared to low yields (30 to 40%) of CN and CS. In terms of the stability of low spiked concentrations (6 to 7 _g), from the surface of glass and stainless steel (60 to 100 cm square), CN rapidly disappeared, CS disappeared gradually, and nonivamide was almost quantitatively recovered. The three lachrymators in absorbent cotton (0.3 g) gradually disappeared. From water (20 mL), nonivamide gradually disappeared and was undetectable after eleven days. CN decreased gradually, and instead, acetophenone appeared. CS disappeared rapidly, and o-chlorobenzaldehyde, o-chlorobenzyl alcohol, and ochlorobenzoic acid were produced. The stability of high spiked concentrations of CN and CS in water (0.5 to 0.6 mg per 20 mL) was also investigated using liquid chromatography. CN was quantitatively recovered. The concentrations of CS decreased to about an8 % recovery level within 2 h. Concomitantly, o-chlorobenzaldehyde appeared at a concentration of about 80% recovery.