Determination of lead in vegetation by a rapid microsampling-cup atomic absorption procedure with solid sample introduction

Abstract

A simple, reagent-free solid-sampling method for determining lead in vegetation is described. The dry sample is ground to a powder and 0.5 g is suspended in 10 ml of deionized water. Aliquots (20 μl) are pipetted into nickel microsampling cups, which are dried at 110°C and inserted into an air—acetylene flame. The resulting lead atomic absorption signal is time-resolved from any non-specific absorption, making further sample pretreatment unnecessary. Suitable dilutions of the suspension provide a linear range of 0.072–240 μg Pb g -1 of dry vegetation. The method is simple, accurate, faster than competitive methods, and provides adequate precision (typically 4.9% r.s.d.) for this application.