Characterization and optimization of HPIC for on-line preconcentration of trace metals with detection by ICP-mass spectrometry

The objective of this study was to investigate the feasibility of using a commercially available cation-exchange column for trace metal preconcentration. In addition, the advantages of interfacing the column to a highly sensitive element-selective detector were examined. A high-performance ion-chromatograph (HPIC) with a high-pressure pump and valve system was used to aid loading and delivery of the mobile phase. An inductively coupled plasma mass spectrometer combination (ICP-MS) was used as a detection device, with interfacing by means of a small diameter liquid-transport tube. The performance of the HPIC/ICP-MS combination was optimized by varying the concentration and flow-rate of two eluents (nitric acid and hydrochloric acid). The effects of varying the sample pH were assessed and the column capacity was determined by "breakthrough" tests. The elements copper, cadmium, mercury and lead were studied; the detection capability was dependent upon the sample volume loaded onto the column. The accuracy of the method was assessed by analysis of an "in house" reference standard.