ELSEVIER Talanta 43 (1996) 1367-1370 Talanta Short communication Anion-exchange enrichment of thallium and cadmium prior to their flame atomic absorption spectrometric determination in soils E. Ivanova”, S. Tsakovski, G. Gentscheva, I. Havezov Received 29 September 1995: revised 30 January 1996; accepted 2 February 1996 Ke~~c~ds: Anion exchange: Cadmium: Soils: Thallium 1. Introduction Thallium and cadmium are among the most toxic environmental pollutants. This makes their determination in soils and other environmental samples a problem of acute importance [ 1.21. The reported natural cadmium content in cultivated Bulgarian soils is 0.1-0.5 /cg g ’ [3]. There are no official data for the thallium content but it is assumed to be of the same order. Since standard reference materials for soils and related samples, especially ones with a certified thallium content, are hard to obtain, the accuracy of methods for trace pollutant determination in such materials is often checked by comparison with the results obtained by independent methods. Conventional flame atomic absorption spec- trometry (AAS) is still widely used despite devel- opments with electrothermal AAS. There are less matrix interferences and related systematic errors with the flame technique. The major limitation of * Corresponding author. flame AAS is poor sensitivity in comparison with electrothermal AAS. Methods for improving the sensitivity of flame AAS using preconcentration and/or special sample introduction have been de- scribed [2]. For example, the use of a slotted quartz tube provides 2.6- and 2.3-fold increases in sensitivity for thallium and cadmium respectively [4]. This sample introduction technique cannot, however, be directly applied to soil digests since the matrix components present severely etch the quartz tube [4]. Therefore a preliminary separa- tion of the analytes from the matrix soil compo- nents is necessary. In our former work [5] the chlorocomplexes of Tl(III) were selectively sorbed on an anion-ex- change resin from the soil digest in 0.1 M HCI. Since cadmium is also sorbed on anion exchang- ers from HCI solutions of relatively low acidity [6]. it was of interest to study the possibilities for the simultaneous anion-exchange separation of Tl( III) and Cd( II) from the soil digest with a view to their subsequent flame AAS determination in the corresponding eluate. 0039-9140 96 Sl5.00 % 1996 Elscvier Science B.V. All rights reserved PII SOO39-9140(96)01898-X