Elemental analysis of chemical wastes by oxygen bomb combustion-ion chromatography

The oxygen combustion bomb-ion chromatography was applied for the analysis of F, Cl, Br, P and S in organic compounds and hazardous wastes using non-suppressed ion chromatography (IC) with indirect photometric detection. A large quantity of CO2 generated during combustion was found to give high levels of carbonate in the sample solution, cause baseline disturbance for IC determination, and give rise to interference for the determination of F−, Cl− and Br− at μg/ml level. The pre-treatment of the absorption solution using ion-exchange resin (H+-form) was shown to remove the carbonate interference while retaining the analyte anions with over 96% recoveries. The determination of low levels of bromide (2 μg/ml) was affected significantly by the presence of nitrate (>25 μg/ml). A large variety of chemical wastes had been analysed using the analytical procedure developed and the reliability of the method was established by parallel method comparison. With linear ranges up to 3 orders of magnitudes and detection limits at sub-μg/ml level, the method developed was found to be applicable for all the wastes encountered except those with high nitrate and low bromide content.