DETERMINATION OF LEAD IN FISH-TISSUES BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY USING BISMUTH NITRATE AS CHEMICAL MODIFIER

The electrothermal atomic absorption spectrometry has been used to develop a routine and interference-free method for the determination of lead in fish tissues. Bismuth(III) nitrate was used as a chemical modifier. The analytical curves of lead were studied by using pyrolytically coated graphite tubes. The instrumental conditions, electrothermal atomizer programme, concentration of the modifier, the calibration and addition curves were studied. A comparative study was also made between Pd(NO3)2 and Bi(NO3)3 as chemical modifiers. Not only a better limit of detection value has been obtained in comparison to Pd(NO3)2 modifier but also a lower atomization temperature, hence an extension of the life period of the graphite tube compared to magnesium nitrate+ammonium dihydrogen phosphate mixed modifier could be achieved in the present method.