Simultaneous and Fast Detection of Anions in Snow Using Short Tube by Capillary Zone Electrophoresis

ISSN： 0306-7319

Source： International Journal of Environmental and Analytical Chemistry, Vol.82, Iss.6, 2002-01, pp. : 353-360

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Abstract

A capillary zone electrophoresis (CZE) method applied short-effective length of capillary (11 cm) and low separation voltage (5 kV) was developed for the fast and quantitative determination of Cl⁻, $ {\rm NO}_2^ - $, $ {\rm SO}_4^{2 - } $, $ {\rm NO}_3^ - $, $ {\rm HCO}_3^ - $ in snow sample. Baseline separation of inorganic anions and organic anions was achieved within 55 s. Indirect absorbance detection of anions was accomplished with a chromate - based background electrolyte modified with cetyltrimethylammonium bromide (CTAB) and acetonitrile at pH 9.5. The effect of the pH, the concentration of electrolyte and modifiers on the resolution was investigated. The application of electrokinetic injection using butyric acid as internal standard created the described method fast, sensitive, and quantitative, with good relative standard deviation (RSD), for migration times from 0.1 to 0.3% and for peak areas from 1.8 to 4.0%. The limits of detection (LOD) were 0.03 mg L⁻¹ Cl⁻, 0.1 mg L⁻¹ $ {\rm NO}_2^ - $, 0.07 mg L⁻¹ $ {\rm SO}_4^{2 - } $, 0.08 mg L⁻¹ $ {\rm NO}_3^ - $, 0.05 mg L⁻¹ F⁻, and 0.2 mg L⁻¹ $ {\rm HCO}_3^ - $, respectively. Standard addition recoveries of Cl⁻, $ {\rm NO}_2^ - $, $ {\rm SO}_4^{2 - } $, $ {\rm NO}_3^ - $, F⁻, and $ {\rm HCO}_3^ - $ in snow sample were between 91 and 104%. This method has been shown promising results for the determination of small anions in snow sample.