A method has been developed for the quantitative determination of various inorganic impurities present in carboxylic acids. The spiked as well as unspiked analytes were subjected to oxidative UV photolysis prior to ion chromatographic analysis. This procedure has definite advantages compared with other sample pretreatment methods: it is a simple procedure and the reagent requirement is minimal. Inorganic cations and anions, except nitrite, nitrate, iodine, sulphite and manganese(II), are unaffected by UV radiation. Depending upon the nature of impurity to be analysed and the amount of carboxylic acid, the UV photolysis time can be adjusted as required. The method was tested on several aliphatic as well as aromatic acids and found to be satisfactory for the determination of chloride, bromide, phosphate, sulphate, iron(III), lead(II), copper(II), zinc(II), nickel(II) and cobalt(II). Detection limits of the proposed method are between 5 and 25 ng/ml and calibration curves were found to be linear up to 1-2 mu g/ml.
