Determination of trace amounts of silver by electrothermal atomic absorption spectrometry after sorption onto dithizone particles in an ultrasonic field

Abstract

Picogram amounts of silver ions in 50 ml of water are quantitatively sorbed onto 0.50 mg of dithizone (approximately 5 µm particle size) by irradiating with ultrasound (20 kHz) for 2 min. After passing the solution through a 1 µm Nuclepore polycarbonate membrane filter, the filter and the dithizone are dissolved in 0.5 ml of chloroform for the determination of silver by electrothermal atomic absorption spectrometry. The proposed method allows the quantitative recovery of silver and the detection of as little as 0.001 µg l^–1 of Ag per sample. Humic and fulvic acids as well as soluble silica do not interfere with the sorption. The time required for a determination is about 15 min.