Fung T, Jeffery W, Beveridge A D
J Forensic Sci. 1982 Oct;27(4):812-21.
"Natural" capsaicin has been identified in "Halt!" sprays by thin-layer chromatography (TLC), high performance liquid chromatography (HPLC), infrared spectrophotometry (IR), and gas chromatography/mass spectrometry (GC/MS). Individual capsaicinoids have been identified as capsaicin, dihydrocapsaicin, and nordihydrocapsaicin. The recommended analytical procedure for small samples is HPLC followed by GC/MS. The alternative procedure of solvent extraction and preparation TLC followed by IR is recommended for large samples.