Appraisal of different electrothermal atomic absorption spectrometric methods for the determination of strontium in biological samples

A comparative study of various potential chemical modifiers (La, Mg, Pd, Ni , Ta, Lu, Sm, Eu, Ho, Er, Tm and Tb) as well as of different background cor rection procedures (deuterium and Zeeman effect) and atomization techniques (wall and platform) for the direct determination of strontium in biologica l samples was carried out. Two instruments, one with deuterium and the othe r with Zeeman effect background corrections have been used to perform the e xperiments. Although La, Mg, Pd, Ta and Lu had a positive effect, lanthanum alone provided the best performance for the determination of strontium in whole blood, urine and bone digests using wall atomization without deuteriu m background correction. However, neither chemical modifier produced any si gnificant improvement in sensitivity when Zeeman effect background correcti on with integrated platform atomization was used. Under the optimized condi tions, the characteristic masses were 0.82 and 2.20pg and the detection lim its (3 sigma) were 0.13 and 0.30 mu g1(-1) with wall atomization and with Z eeman effect background correction respectively. Recovery studies and analy sis of standard reference materials certified for strontium were performed to assess the accuracy. The results for the determination of strontium in r eal samples with wall atomization and lanthanum as chemical modifier, agree d well with those obtained with Zeeman effect background corrector with a p recision typically between 0.5 and 3%. Both procedures can be recommended, and the choice will depend on instrument availability. (C) 1999 Elsevier Sc ience B.V. All rights reserved.