Abstract
Mercury (Hg) is one of the most toxic elements impacting on human and ecosystem health. Each form of Hg possesses different physicochemical properties and toxicity profiles. In aquatic environments, the transformation of Hg species makes Hg more prone to biomagnification and bioaccumulation in food chains. In humans, food chain is the predominant route of exposure to Hg while urine is the excretory route. Thus, the concentration of Hg species in water and urine samples is conductive to assessing long-term body exposure. Nevertheless, the determination of Hg is still a challenge for analytical scientists due to the low-level of Hg and complex matrix in samples. To overcome these challenges, we developed a ultrasensitive and highly matrix tolerant microfluidic-based vapor generation (VG) system to couple with high-performance liquid chromatography (HPLC) separation and inductively coupled plasma-mass spectrometry (ICP-MS) detection for the determination of Hg species. The VG system exploited poly(methyl methacrylate) (PMMA) substrates of high optical quality to fabricate a microfluidic-based photocatalyst-assisted reduction device (microfluidic-based PCARD). Under the optimized conditions, the HPLC/TiO2-coated microfluidic-based PCARD/ICP-MS system enabled us to achieve detection limits of 1.39 and 2.95 ng L −1 for mercuric mercury (Hg2+) and methylmercury (MeHg+), respectively. Both Hg2+ and MeHg+ could be efficiently vaporized within 15 s, while a series of validation experiments indicated that our proposed method could be satisfactorily applied to the determination of Hg species in both human urine and environmental water samples.