Sensitive and selective spectrofluorimetric determination of chromium(VI) in water by fluorescence enhancement

Abstract: A new fluorogenic method for the selective and sensitive determination of chromium(VI) in acidic water using rhodamine B hydrazide was developed. This method was based on the oxidation of non-fluorescent rhodamine B hydrazide by potassium dichromate in acidic aqueous conditions to give rhodamine B, which was highly fluorescent, as a product. With the optimum condition described, the fluorescence enhancement at 585nm was linearly related to the concentration of chromium(VI) in the range of 5.0×10−8 to 2.0×10−6 molL−1 (2.60–104ngmL−1) with a correlation coefficient of R 2 =0.9993 (n =18) and a detection limit of 5.5×10−9 molL−1 (0.29ngmL−1). The R.S.D. was 2.2% (n =5). The proposed method was also applied to the determination of chromium(VI) in drinking water, river water and synthetic samples. [Copyright &y& Elsevier]