New approaches to the direct analysis of highly saline samples by FIA-ICP-MS

The direct FIA-ICP-MS determination of Al, As, Cr, Mn, Mo, Ni, Ph, Rh, Sb, Te, and V in saline matrixes with different total dissolved solids content (TDS) (0.03-30%) was studied. Sample introduction by FIA permits the nebuli zation of matrixes with higher TDS in the ICP-MS. In this way, the direct d etermination of Mo and Mn in a certified seawater sample (CASS-3) was succe ssfully carried out and the results obtained were in good agreement with th e certified values. The other elements studied were either available in ver y low concentrations or do not have certified values for the CASS-S sample. The study of the influence of the instrumental parameters, such as nebuliz er gas flow and plasma power, showed that the intensity obtained for the di fferent elements studied decreases with matrix concentrations of 3% TDS or more. The higher the saline concentration, the smaller a flow is needed to minimize the interferences caused by the matrix. With regard to plasma powe r, it was observed that an increase in power reduces both spectroscopic and non-spectroscopic interferences. A study of the recoveries showed that Al, As, Cr, bin, Mo, Ni, Pb, Rh, Sb, Te, and V can be determined directly by F IA-ICP-MS depending on the dissolved solids content. Mn and Mo can be deter mined directly in matrixes with 30% TDS or less; Sb and Pb with 15% TDS or less; Rh and Te with 3% TDS or less; ill and Cr with 0.3% TDS or less; and all elements cited can be determined directly in matrixes with 0.03% TDS.