Fig. 1.
Typical chromatograms of trans-3′-hydroxycotinine (A), cotinine (B), and 11-nor-9-caiboxy-Δ9-tetrahydrocannabinol (C) obseived in solvent blank (1), lowest calibrant (2), and unknown mine samples (3). Note: The concentrations of trans-3′-hydroxycotinine, cotinine, and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in unknown samples are 22.2 (A3), 10.5 (B3), and 11.3 ng/mL (C3), respectively.