In situ matrix evaporation by isothermal distillation of high-purity reagents for the determination of trace impurities by ion chromatography

In situ matrix evaporation of high-purity acids based on isothermal distillation was achieved in a high-density polyethylene (HDPE) container on a water bath, to avoid contamination from the laboratory environment. The solubility of water and acid vapours in glycerol due to co-association was utilized to achieve complete evaporation. All major sources which contribute to the process blank were taken care of in a simple and effective way. A 50-fold preconcentration with >99.9% matrix removal was achieved for the analysis of low-boiling acids, HCl, HF, HNO3 and H2O2. The non-volatile ions NH4+, Li+, Na+, K+, Mg2+, Ca2+, SO42− and PO43− were determined by ion chromatograph with conductivity detection. The detection limits were 6–130 ng/l with recoveries of 85–110% for all ions studied.