Table 4.

The intra- and inter-day precision and accuracy of the LC-MS/MS method used to quantify cocaine and its related compound in whole blood samples

Drug	Intra-day						Inter-day
	L		M		H		L		M		H
	CV (%)	Bias (%)	CV (%)	Bias (%)	CV (%)	Bias (%)	CV (%)	Bias (%)	CV (%)	Bias (%)	CV (%)	Bias (%)
Cocaine	10.3	−11.1	7.1	4.5	4.0	0.3	10.8	−13.3	2.0	2.2	0.6	0.9
EME	8.0	−2.9	4.0	−0.4	3.5	−3.2	7.8	−8.8	3.2	3.3	2.7	−0.2
BE	11.1	−13.6	5.9	−0.7	7.1	−4.4	0.7	−14.8	1.1	0.6	1.9	−3.2
ECG	12.5	9.7	10.9	−3.7	5.2	1.2	6.9	3.5	2.9	−0.5	4.3	1.7
Norcocaine	2.5	11.8	2.9	2.3	7.9	9.9	0.9	12.8	1.1	3.4	1.6	11.5
NEME	9.8	11.9	4.2	−6.4	5.9	10.2	13.6	8.5	7.0	−11.1	2.3	12.6
Cocaethylene	4.1	−11.6	2.0	1.7	5.8	−1.1	1.9	−10.4	0.5	1.2	1.1	−2.3
EEE	8.2	5.7	3.2	1.1	3.4	5.6	7.7	−1.1	6.4	−5.9	4.3	10.1
Norcocaethylene	2.2	13.5	4.7	3.3	7.4	1.2	1.2	15.0	1.2	1.8	1.4	2.9
NEEE	5.9	12.5	3.5	−4.1	6.0	7.2	11.9	11.4	1.6	−5.8	0.6	7.8

Low concentration: 1.9–3.2 ng/ml (0.01 µM); Medium concentration: 95–160 ng/ml (0.5 µM); High concentration: 190–320 ng/ml (1 µM)