Biomedical subjects

P B Stockwell

Publications and source records attributed to P B Stockwell.

7 recordsLinked to original sources

PubMed1994

Rapid method for the determination of total mercury in urine samples using cold vapour atomic fluorescence spectrometry.

A rapid method for the determination of total mercury in urine samples is proposed. Samples are digested using a bromination procedure at room temperature. Analysis is performed using automated continuous flow vapour generation coupled to atomic fluorescence spectrometry. This approach allowed the analysis of 30 samples per hour and a limit of detection of 1 ng l-1. The analytical procedure was assessed using certified reference material NBS 2672a freeze-dried urine and two batches of Seronorm trace elements in urine samples.

Cold Temperature↗

PubMed1990

Use of masking agents in the determination of lead in tap water by flame atomic absorption spectrometry with flow injection pre-concentration.

The selectivity of immobilised 8-hydroxyquinoline for lead is shown to be improved by the use of masking agents during pre-concentration, prior to determination by flame atomic absorption spectrometry. Interference by iron, copper, aluminium and zinc is suppressed by including triethanolamine, thiourea, fluoride, acetylacetone or cyanide in the buffer as masking agents. Species such as iron or copper can completely prevent the pre-concentration of lead. This is shown to be overcome by using a buffer consisting of 0.2 M boric acid, 2% triethanolamine, 2% thiourea and 2% acetylacetone, even when the interfering species is in a 200-fold excess over lead. Recoveries from tap water samples, to which various amounts of lead had been added, ranged from 94 to 108%. Results of analyses of tap water samples using this method were in good agreement with those obtained by electrothermal atomic absorption spectrometry.

Indicators and Reagents↗

PubMed1978