Jornal de Química Analítica Ambiental

Determination of Selenium in Environmental Samples Using Hydride Generation Coupled to Atomic Absorption Spectroscopy

Abstract

Busheina IS, Abobaker MM, Aljurmi ES and Etorki AM*

A hydride generation coupled to atomic absorption spectroscopy HGAAS method is presented for the determination of Selenium content in soil samples, alfalfa, animal feed, and water samples. The selenium distribution was studied in various locations in Zawia city. The studied areas were divided to seven different zones. The samples were digested in a mixture of mineral acid (HNO3, HCL, HCLO4 and H2O2). The Selenium element in acidified sample solution was reduced directly by treating it with Sodium borohydride (NaBH4), the metal hydride was introduced to the atomizer of AAS by inert carrier gas (N2, He). The instrument used for the generation of hydride was home built in the analytical lab and a batch method was implemented. The analytical parameters were optimized throughout the analytical procedure to give typical sensitivity (0.0055 pg/g). The Atomic Absorbance profile was recorded for all measured samples; the obtained signal profiles show smooth peaks. The Absorption value at the peak height was used as a basis for the analytical calculations. A calibration curve of standard selenium concentrations against absorbance was plotted and used to determine the selenium concentration in each sample. Soil samples were analysed by (HGAAS) for determination of concentration of selenium results are reported for all the studied zones, some zones did not exceeded the reported critical toxicity values (1.0-5.0 pg/g), but another zones are relativity high (5.6-5.9 pg/g). The Selenium content in alfalfa from different zones are relatively low in the range of (0.7 to2.20 pg/g). Concentrations of selenium in some animal feed samples are relatively low and showing deficiencies (0.62-0.71 pg/ g), but other samples are relatively high and were close to the lower limits for high dose (1.41-1.98 ng/g).