Sono-electroanalytical determination of lead in saliva
Lead poisoning is recognized as a major environmental health risk and blood tests are used to assess occupational or domestic exposure to lead. Evidence has suggested that salivary lead concentration is closely related to recent lead exposure and may provide a useful and non-invasive indicator of le...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2002
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| Summary: | Lead poisoning is recognized as a major environmental health risk and blood tests are used to assess occupational or domestic exposure to lead. Evidence has suggested that salivary lead concentration is closely related to recent lead exposure and may provide a useful and non-invasive indicator of lead status. Sono-electroanalysis has been shown to enhance detection of heavy metals in biological and environmental samples via the phenomena of acoustic streaming and cavitational shearing. This article therefore discusses the applicability of ultrasound enhanced square-wave anodic stripping voltammetry for the detection and determination of lead in saliva at an in situ plated Nation coated mercury thin film glassy carbon electrode. Quantitative analysis of lead in artificial saliva from a realistic sputum volume, 220 μL, introduced to acetate buffer was shown to be possible. Employing an insonated preconcentration obviated the need for lengthy or degradative sample pretreatment by liberating the lead from the glycoproteins and other materials to which it binds in solution. Rapid experimental time was facilitated by short preconcentration periods of 120 s, due to the enhanced mass transport afforded by acoustic streaming. Quantitative depassivation of the electrode surface by cavitational shearing maintained the analytical signal throughout the experiment where under silent conditions the signal diminished to zero with time. Linear standard addition plots intersect the origin as predicted for samples uncontaminated with lead and exhibit R2 values between 0.988 and 0.994. The detection limit in the analyte is 0.25 μL-1 which for a 220 μL sputum size corresponds to 38 μL. With the onset of lead poisoning at a blood lead concentration of 100 μL-1 this technique accesses biologically relevant lead levels. |
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