PREPARATION AND CHARACTERIZATION OF A CODEINE RESPONSIVE ELECTRODE

The behaviour of codeine reineckate and codeine tetraphenylborate memb rane electrodes has been observed with a respective Nernstian response of 58 and 56 mV/decade for 9.3 x 10(-5)-1.3 x 10(-3) M codeine sulfat e solutions. The working pH ranges were 5-8 and 4-8, respectively. The selectivity towards sugars, amines, amino acids, cations, and some ph armaceutical compounds was found to be satisfactory. The isothermal te mperature coefficient was 0.0014 V/degrees C. The electrodes were appl ied successfully for the determination of codeine in some pharmaceutic al dosage forms with a relative standard deviation range of 0.16-0.30% and an average recovery of 98.6 +/- 0.6%.