Determination of mercury and selenium in herbal medicines and hair by using a nanometer TiO_2-coated quartz tube atomizer and hydride generation atomic absorption spectrometry

摘要

The nanometer TiO_2 particle was coated onto the inner wall of a T-shaped quartz tube atomizer (QTA) and then was used as a new atomizer (NT-QTA) for the determination of Hg and Se by hydride generation atomic absorption spectrometry (HCAAS). After coating 67.4 mg TiO_2 on a quartz tube, the analytical performance of NT-QTA-HGAAS was compared to conventional QTA-HGAAS and it was improved as follows: (a) the linear range of the calibration curves was expanded from 10.0-80.0 ngmL~(-1) to 5.0-150.0 ngmL~(-1) for Hg, and from 10.0-70.0 ngmL~(-1) to 5.0-100.0 ngmL~(-1) for Se;(b) the characteristic concentration of was decreased from 2.8 ngmL~(-1)/l% to l.lngmL~(-1)/l% for Hg and from 1.2ngmL~(-1)/l% to 0.8 ngmL~(-1)/l% for Se: and (c) the interference from the coexistence of As on the determination of Hg and Se could be eliminated. The achieved technique was applied for the determination of Hg and Se in herbal medicines and hair.