Table 1.

The results of precision, accuracy, and recovery studies for morphine and codeine in human urine (n = 6).

Compound	Concentration	RSD (%)		RE (%)		Recovery (%)
	(ng/mL)	Intraday	Interday	Intraday	Interday
Morphine	50	4.3	8.2	−0.3	−6.5	86.1
	200	4.4	7.4	−5.2	−10.1	75.5
	1600	5.3	9.3	−6.9	5.7	80.2
Codeine	50	10.5	13.0	8.5	−7.3	78.9
	200	11.4	9.8	−3.9	−12.8	79.7
	1600	5.2	12.9	−9.9	−8.2	86.8