Determination of lead by hydride generation inductively coupled plasma mass spectrometry Original Research Article

A method for the determination of lead by hydride generation inductively coupled plasma mass spectrometry was explored using oxalic acid–ammonium cerium(IV) nitrate-sodium tetrahydroborate as the reaction matrix and a homemade hydride generator. The sensitivity achieved was ca. 7.5 times higher than that obtained using an ultrasonic nebulizer. The detection limit (3σ) and the signal precision (R.S.D., n=13) were 0.007 μg l−1 and 0.21% for 1 μg l−1 Pb, respectively, Fe(III) or Ni(II) up to 10 mg l−1 did not affect the hydride generation of 1 μg l−1 Pb. Additionally, the present system equipped with an injector valve and a 500 μl sample loop was also operated in the flow injection mode. Because of the short memory effect (typically 25–30 s), six replicate injections of a solution containing 4 μg l−1 Pb were performed within 5 min. The R.S.D. values (n=13) were 0.33 and 1.41% for peak height and area measurements, respectively. The method was applied to the determination of lead in three environmental reference materials involving natural water, plant tissue and pond sediment. Good agreement was obtained between the certified values and the experimental results with the precisions (R.S.D., n=5) less than 1.0% for both continuous and flow injection modes.