DETERMINATION OF ORGANIC LEAD IN SOILS AND WATERS BY HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

This paper describes a simple and rapid method for the determination o f the sum of tetraalkyllead (TAL) compounds (Me4Pb, Et4Pb) and their i ntermediate decomposition products, the trialkyllead (Me3Pb+, Et3Pb+) and dialkyllead (Me2Pb2+, Et2Pb2+) species. The lead species in soluti on are transformed into the corresponding hydrides by sodium tetrahydr oborate and directly introduced into the ICP torch, Hydride generation takes place in a continuous Bow hydride generator and the products ar e fed into an inductively coupled plasma atomic emission spectrometer, This arrangement avoids the necessity for solvent extraction and samp le transfer. The reaction conditions (argon flow rate, concentration o f acid and concentration of sodium borohydride) have been optimized, T he acid is decisive for obtaining strongly different sensitivities for organic lead and inorganic lead; 2.0% (m/v) citric acid suppresses th e signal of inorganic lead and this offers the possibility to determin e the organolead compounds in the presence of excess amounts of inorga nic lead, thus characterizing the method as a screening method. Linear calibration for six organolead compounds of varying polarity (neutral and ionic species) was established over the concentration range of 0. 1 to 100 mu g l(-1). Spiked natural water and soil samples were analyz ed by this method with recoveries of 71-107%, Best extraction efficien ces were found for a mixture of 5 ml of 1% ammonical methanol and 5 ml of 0.2 M sodium acetate, The optimized method was tested for soil sam ples with varying matrices and a wide range of concentrations of alkyl lead obtained from an old industrial production site.