Optimization of A Portable Microanalytical System to Reduce Electrode Fouling from Proteins Associated with Biomonitoring of Lead (Pb) in Saliva

Journal Article · Thu Sep 15 00:00:00 EDT 2005 · Talanta

DOI:https://doi.org/10.1016/j.talanta.2005.03.039· OSTI ID:15020817

Yantasee, Wassana; Timchalk, Chuck; Weitz, Karl K; Moore, Dean A; Lin, Yuehe

There is a need to develop reliable portable analytical systems for on-site and real-time biomonitoring of lead (Pb) from both occupational and environmental exposures. Saliva is an appealing matrix since it is easily obtainable, and therefore a potential substitute for blood since there is a reasonably good correlation between Pb levels in both blood and saliva. The microanalytical system is based on stripping voltammetry of Pb at the microelectrochemical cell having a flow injection/flow-onto design. Samples that contain as little as 1% saliva can cause electrode fouling, resulting in significantly reduced responsiveness, irreproducible quantitations, and the need for frequent electrode regeneration. In addition, incomplete Pb release from salivary protein can also yield a lower Pb response than expected. This paper evaluates the extent of in vitro Pb-protein binding and the optimal pre-treatment for releasing Pb from the saliva samples. Even in 50% by volume of rat saliva, the electrode fouling was not observed, due to the appropriate sample pretreatment (with 1.0 M acid, followed by centrifugation at the RCF of 15200?g) and the constant flow of the sample and acidic carrier that prevented passivation by the protein. The system offered a linear response over a low Pb range (1-10 ppb), low detection limit (1 ppb), excellent reproducibility (5% RSD), and reliability. It also yielded the same Pb concentrations in unknown samples as did the ICP-MS. These encouraging results suggest that the microanalytical system represents an important analytical advancement for real-time non-invasive (i.e., saliva) biomonitoring of Pb.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15020817
• Report Number(s): PNWD-SA-6834; 11098; TRN: US200521%%369
• Journal Information: Talanta, Vol. 67, Issue 3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BLOOD
CENTRIFUGATION
DESIGN
ELECTRODES
ENVIRONMENTAL EXPOSURE
FOULING
IN VITRO
OPTIMIZATION
PASSIVATION
PROTEINS
REGENERATION
RELIABILITY
SALIVA
SENSITIVITY
environmental molecular sciences laboratory
lead
electrochemical sensor
saliva
protein
stripping voltammetry
electrode fouling
passivation