FIELD DETECTION OF ANTIMONY AND THALLIUM IN SOIL

A rapid field procedure for spectrophotometric determination of availa ble amount of antimony (Sb) and thallium (Tl) in soil is described. Th ey are extracted from soil by equilibrating with 0.1M hot hydrochloric acid (60 degrees C). Antimony(V) and Tl(III) are preconcentrated by t he solvent-extraction procedure with basic organic reagents, i.e. N,N' -diphenylbenzamidine (DPBA) and surfactants (CTAB, CPC), respectively, into toluene, and the extracts are allowed to react with basic dye, b rilliant green (BG) in sequence. The molar absorptivity of the Sb and Tl complexes are (1.54) x 10(5) and (1.63-1.70) x 10(5) L/mole/cm, res pectively, at absorption maximum 640 nm. The method is free from inter ferences of almost all metal ions which are commonly associated with t hem in soil. The present method is applicable for the field detection of soil contamination of Sb and Tl at lower ppb levels.