Voltammetric Determination of Codeine on Glassy Carbon Electrode Modified with Nafion/MWCNTs

Table 1

Results of codeine determination in various samples.

Codeine added	Codeine found (recovery %)
	Urine; (mg/L)	Human plasma; (mg/L)	Syrup^1; (mg/10 mL)	Tablet^2; (mg/tablet)
0	0	0	15.5 ± 0.7	15.3 ± 0.4
0.15 mg/L	0.144 ± 0.009; (96)	0.138 ± 0.012; (92)	—	—
0.6 mg/L	0.632 ± 0.027; (105)	0.57 ± 0.03; (95)	—	—
15 mg	—	—	31.4 ± 1.1; (103)	30.9 ± 0.9; (102)

Product declared 15 mg/10 mL.
²Product declared 15 mg/tablet.