Selenium in municipal wells in the Irapuato City — spectrofluorimetric determination with 2,3-diaminonaphthalene

Abstract

A chromatographic procedure with spectrofluorimetric detection (λ = 257 nm, λ = 548 nm) is proposed in this work for Se determination in well water after formation of a piazselenol compound. The low detection limit obtained (15 ng·l^-1 ) enabled minimisation of the sample size and, consequently, smaller amounts of reagents were needed. Selenium content was confirmed using standard reference material. The proposed procedure was applied for the determination of Se in municipal wells in Irapuato city (Lerma-Chapala basin) and the obtained results showed that 52.5% of the analysed wells contained amounts higher than the limit 10 μg·l^-1 of selenium as recommended by the World Health Organisation for drinking water. The high selenium levels were found only in the wells of the city of Irapuato (concentration range 12 – 223 μg l^-1 ), not in the wells in other cities of the State of Guanajuato. No contamination by other trace elements (arsenic, cadmium, chromium, iron, manganese, lead) was found in Irapuato wells.