| Abstract: |  A catalytic kinetic spectrophotometric method is developed for the determination of trace amounts of Cu(II). It is based on the catalytic effect of Cu(II) on the oxidation of cysteine (RSH) by hexacyanoferrate(III) in acidic medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of hexacyanoferrate(III) at 420 nm. The optimum operating conditions regarding concentration of reagents, pH and temperature were established. The working curve is linear in the concentration range of 0–6.35ng·mL–1. The maximum percentage error and standard deviation for determination of Cu(II) in the range of 1.27–6.35ng·mL–1 have been calculated to be 3.9 and 0.4 respectively. The detection limit calculated was 0.15ng·mL–1. The interference effect of several species was also investigated, and it was found that the most common cations and anions do not interfere with the determination. The developed procedure was successfully applied to the determination of Cu(II) in various synthetic and real samples. The typical feature of this procedure is that determination can be carried out at 25°C and/or in the absence of any precision thermostatic bath in the very short analysis time of one minute. The newly developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity compared to other kinetic methods.Received October 8, 2002; accepted April 7, 2003Published online July 16, 2003 |
