Development of chip-based photocatalyst-assisted reduction device to couple high performance liquid chromatography and inductively coupled plasma-mass spectrometry for determination of inorganic selenium species

•The PMMA chip was first developed for online vaporization of inorganic Se species.•Analytical signals were significantly enhanced by using our developed system.•The most exciting of the proposed system is its high performance with low cost.

In this study, a poly(methyl methacrylate) chip-based photocatalyst-assisted reduction device (PMMA chip-based PCARD) was developed as a reactor based on its excellent optical properties and ease of fabrication. Its transmittance of ultraviolet light at 365 nm (UV365) was found to be as high as 92% using a PMMA of 2 mm thickness. To optimize the vaporization efficiency, the effect of varying the depth of the geometry trenched on the PMMA-based chip was investigated. After optimization, it required only 29 s of UV365 irradiation to vaporize the selenium (Se) species of interest. The PMMA-based chip was successfully used as an interfacing device for the hyphenation of high performance liquid chromatography (HPLC) separation and inductively coupled plasma-mass spectrometry (ICP-MS) detection. Additionally, under the optimized conditions for vaporization, using 1 g L−1 titanium dioxide nanoparticles (nano-TiO2) at pH 5, we found that Se(IV) and Se(VI) were converted quantitatively into volatile Se products. In addition, the optimized vaporization efficiency of the Se species of interest for the online HPLC/PMMA chip-based PCARD/ICP-MS system enabled us to achieve detection limits for Se(IV) and Se(VI) in the nanogram-per-liter range (based on 3σ). A series of validation experiments indicated that our proposed methods could be applied satisfactorily to the determination of inorganic Se species in environmental water samples.