COMPARISON OF 4 NEBULIZER-SPRAY CHAMBER INTERFACES FOR THE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF ARSENIC COMPOUNDS USING INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRIC DETECTION

Four nebulizer-spray chamber combinations mere used and evaluated as i nterfaces for HPLC with ICP-MS detection, The oscillating capillary ne bulizer (OCN), the concentric nebulizer and the Meinhard high-efficien cy nebulizer (HEN) were used with single pass, double pass and cycloni c spray chambers, Monomethylarsonic acid, dimethylarsinic acid, arseno betaine and arsenocholine were separated using an ion-pair liquid chro matographic method on a C-18 column. A calibration curve, limits of de tection, precision for five injections, peak efficiency and peak asymm etry were calculated for each compound using each nebulizer-spray cham ber combination. The HEN with cyclonic spray chamber displayed the low est detection limits (1.0-2.3 mu g l(-1) for the four arsenic compound s) and had the lowest precision of duplicate injections (RSD as high a s 14%). The concentric nebulizer had reasonably low detection limits; the standard nebulizer had lower detection limits (1.6-3.6 mu g l(-1)) than the cyclonic spray chamber (4.5-11 mu g l(-1)). The OCN had the highest detection limits under chromatographic conditions identical wi th those for the other interfaces (160-360 mu g l(-1)). The precision (RSD) of duplicate injections for the concentric nebulizer and the OCN ranged from 2.1 to 8.6%.