Abstract
It has been widely recognized that mercury is hazard for human beings; chronic exposure to mercury can cause a series of health issues. Because mercury is excreted from the human body to urine and the concentration of urinary mercury is closely related to the body content, the level of urinary mercury is considered as a representative of exposure biomarkers for mercury poisoning. However, the concentration of mercury in urine are typically at or below micrograms per liter level, leading accurate and rapid determination of mercury in urine samples remains as a challenge. Thus, the development of sensitive and reliable analytical techniques that are capable of measuring nanogram levels of mercury is of great interest. To meet the requirements, in this study, we developed an ingenious methodology involving titanium dioxide nanoparticle (nano-TiO2)-assisted preconcentration/in-situ vapor generation chip and inductively coupled plasma-mass spectrometry (ICP-MS) for on-line determination of mercury. The analytical reliability of the proposed system was confirmed by using it to analyze the certified reference materials—Seronorm Trace Elements Urine L-2 (freeze-dried human urine). Based on the obtained results, the dramatically reduction of hazard consumption and “hands-on” manipulation enabled the realization of a simplified and relatively clean procedure with extremely low detection limits (3σ, n=7) of 0.75 ng L–1 for detecting inorganic mercury in 500-μL samples. A series of validation experiments indeed indicated that our developed technique could be satisfactorily applied to the determination of mercury in urine samples. To the best of our knowledge, this is the first study to report the direct exploitation of nano-TiO2 for on-line sample preconcentration and in-situ vapor generation prior to ICP-MS measurement.