Enzymatic Digestion and Selective Quantification of Underivatised Delta-9-Tetrahydrocannabinol and Cocaine in Human Hair Using Gas Chromatography-Mass Spectrometry

Table 1

Summary of assay validation results.

Compounds	Recovery (%) at 0.5 ng/mg (𝑁=6)	Concentration (ng/mg)	Precision RSD (%)		Accuracy (%)
			Intraday 𝑛=6 per each	Interday 𝑛=18 per each
Δ^9-THC		0.02	15.4	18.0	114
		0.10	15.6	7.0	110
	102.2	0.50	8.0	5.0	95
Cocaine		0.05	12.1	10.6	98
		0.10	10.1	12.1	101
	96.5	0.50	5.1	2.8	110