Online Preconcentration Procedure for Chromium Speciation and Determination in Industrial Water Samples Using Flame Atomic Absorption Spectrometry

An online preconcentration system based on solid-phase extraction was developed for speciation and determinations of Cr in industrial water samples using flame atomic absorption spectrometry. A minicolumn packed with Amberlite XAD-16 loaded with salicylic acid was used to preconcentrate chromium species. All flow and chemical parameters that influence sorption were studied. The preconcentration factor and detection limit for the preconcentration time of 120 s were 79 and 0.10 mu g L-1, respectively. The concentration of Cr(VI) species was calculated by the difference of the total Cr and Cr(III). The relative standard deviation (RSD) (five replicate of measurements) for 50 and 100 mu g L-1 Cr(III) solution was 1.2 and 1.0% respectively. The accuracy of the method was verified by analyzing a standard reference material (NIST SRM 1640a, trace elements in natural water). The proposed preconcentration method was successfully applied to the determination of Cr species in industrial water samples with satisfactory results.