STUDIES OF THE SIMULTANEOUS DETERMINATION OF TRACE-METALS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Simultaneous determination methods for trace metals have been studied by high-performance liquid chromatography (HPLC) with photometric dete ction. The metals to be determined were extracted into the organic pha se of a small volume or enriched on a C18 mini-column as their metal c helates. The extracted or enriched metal chelates were separated on a C18 analytical column and then detected with the usual type photometri c detector. Some dithiocarbamates and beta-diketonates were used as ch elating agents. The HPLC methods combined with solvent extraction enab led a multielement analysis of ng/ml (ppb) levels of Cd, Ni, Pb, Zn, C u, Hg, Co, and Bi in a 50-ml water sample. The methods were applied to multielement analyses of river water as well as several standard refe rence materials. The results showed good agreement with those of AAS o r certified values. An on-line column enrichment method was also used for the simultaneous determination of Cd, Ni, Pb, Cu, Hg, Co, and Bi. To a 2-ml sample solution, 400 mul of a buffer solution, 100 mul of 0. 01 M hexamethylenedithiocarbamate (HMDC) and 5 mul of chloroform were added. Then, a 2-ml aliquot of the resultant solution was injected ont o a C18 minicolumn. The enriched HMDC chelates were then separated on a C18 analytical column. The detection limits were 0.04 to 0.55 ppb, d epending on the metals. The method was applied to a multielement analy sis of tap water.