Voltammetric determination of codeine on glassy carbon electrode modified with Nafion/MWCNTs

A glassy carbon electrode modified with a nafion/mwcnts composite is shown to enable the determination of codeine using differential pulse voltammetry in phosphate buffer of ph 3.0. at a preconcentration time of 15 s,the calibration graph is linear in the 0.5 μm (0.15 mg·l-1) to 15 μm (4.5 mg·l-1) concentration range with a correlation coefficient of 0.998. the detection limit at a preconcentration time of 120 s is as low as 4.5 g·l-1. the repeatability of the method at a 0.6 g·l-1 concentration level,expressed as the rsd,is 3.7% (for n=5). the method was successfully applied and validated by analyzing codeine in drug,human plasma,and urine samples. © 2015 robert piech et al.