DETERMINATION OF TRACE METALS IN SEA WATER BY ICP-MS AFTER MATRIX SEPARATION
Chandra K. Sekhar,* Sreedhar N. Chary, Kamala C. Tirumala, and V. Aparna
Analytical Chemistry & Environmental Sciences, Indian Institute of Chemical Technology, Hyderabad, (A.P), India, 500 007
The analysis of ultra trace elements in sea water samples is one of the most difficult analytical tasks in the field of environmental monitoring, as extremely low detection limits for elements buried in a highly saline matrix is required. The use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for direct sea water analysis is currently limited by spectral and non-spectral interferences caused by the sea water matrix. Sample dilution is always a way out at the expense of inadequate sensitivity after such dilution especially for open ocean sea water. In order to approach this complex analytical task by ICP-MS there are two common strategies studied so far: first the use of pre-concentration technique and matrix removal and second the use of double focussing ICP-MS instruments. The use of Ammonium tetramethylene dithiocarbamate (APDC)/Methyl isobutyl ketone (MIBK) solvent extraction for matrix removal and direct estimation of trace elements in sea waters by ICP-MS are discussed in this paper.