Determination of indium in water samples using solid-phase extraction with modified silica gel and slurry sampling with electrothermal atomic absorption spectrometry

Indium in drinking water was determined using solid-phase extraction with modified silica gel followed by the electrothermal atomic absorption spectral analysis of slurries. The formation regularities of the analytical signal for this element in the presence of the sorbent phase favoring a high background absorption were studied. Preconcentration was carried out using a modified silica gel with covalently immobilized azolium groups. (The particle size was 40–60 µm). Conditions for the correct measurement of analytic signal for the element, such aspyrolysis and atomization temperatures, maximum permissible concentration of slurry, and method of calibration curve plotting and its linearity range, were determined. The achieved limit of detection (3σ) and limit of quantification (10σ) were 5.5 and 18 ng/L, respectively. The preconcentration factor was 200. The developed analysis scheme was applied with success to determine indium in real samples of bidistilled, drinking, and mineral water.