Direct determination of trace metals in solid samples by atomic absorption spectrometry with electrothermal atomizers: Part 4. Interference effects in the determination of lead and bismuth in steels

The origin of observed interference effects is investigated by comparing signals obtained for lead and bismuth before and after the addition of different matrix components. It is concluded that the applicability of the solid-sampling technique should be related to the solubility of the impurity in the matrix components and to the volatilities of the impurity and matrix. The extent to which trace elements are removed from steels is similarly established by using steels and graphite pieces to which the element was added. The samples are introduced under isothermal conditions and peak areas are evaluated. It is found that 80% of lead or bismuth is recovered from stainless steel at 2100°C. Thus standardization against aqueous solutions gives inaccurate results for solid samples.