Sensitive spectophotometric determination of microamounts of paracetamol using an indirect redox technique

A sensitive spectrophotometric method for the determination of microamount of paracetamol Is described, based on the oxidation of the drug by Fe (III) in the presence of ferrozine, whereby reduced Fe (II) reacts to build a fe rrozine complex. The platter exhibits an absorption maximum at 562 nm with an apparent molar absorptivity of 2.81x10(4) Lmol(-1)cm(-1) and a Sandell s ensitivity of 5.4 ngcm(-2). The optimum concentration range is 0.1-8.0 mug mL(-1) of paracetamol. For more accurate results Ringbom optimum concentrat ion range is 0.25-7.50 mug mL(-1). The regression equation is A = 0.186 C 4 x 10(-3) (where C is the concentration in mg mL(-1)) with a correlation coefficient of 0.9999 (n=10). Statistical analysis indicated that the re wa s no significant difference between the results obtained by the proposed me thod and those of the British Pharmacopeia method. The method was successfu lly applied to the determination of paracetamol in some pharmaceutical form ulations.