Determination of gold in sludge and soil by sequential ICP-AES after preconcentration and separation with thiol-cotton fibre

Summary A method is presented for the determination of gold in sludge and soil samples by sequential ICP-AES after preconcentration and separation from the common alkali and alkaline-earth metals, as well as other matrix components, e.g. iron, by a thiol-cotton fibre column. The cotton fibre, impregnated with thioacetic acid, quantitatively adsorbs gold, thus eliminating the severe spectral interferences encountered by direct ICP-AES analysis. After preconcentration and separation the results obtained at Au 242.795 nm and Au 267.595 nm agree with each other. A quantitative recovery for added spikes was obtained. The method allows the determination of gold in complex matrices such as soil or sludge samples that have been proven to be impossible by conventional ICP-AES without separation from the matrix.On leave from Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 2000 50, China