Amine-functionalized titanium metal organic framework for photochemical vapor generation for determination of selenium by inductively coupled plasma optical emission spectrometry

Metal organic framework MIL-125-NH2 was used as a photocatalyst for the photochemical vapor generation to establish an efficient and accurate method for highly sensitive determination of trace selenium by inductively coupled plasma optical emission spectrometry. The mixture of Se (IV) and Se (VI), MIL-125-NH2 nanoparticles and a low molecular weight organic acid was mixed to generate gaseous selenium-containing species which was separated from its liquid phase and transported to inductively coupled plasma optical emission spectrometer for determination. Influencing factors including carrier gas flow rate, type and concentration of catalyst, type and concentration of organic acid, UV irradiation time and power, and sample pH were carefully studied. Under the optimized conditions, a catalytic efficiency of more than 80% was achieved. The limits of detection for Se (IV) and Se (VI) were found to be the same and as low as 0.3 ng/mL. The relative standard deviation of Se (IV) and Se (VI) was 2.7% and 2.1% at 20 ng/mL (n = 11), respectively. The accuracy of the method was evaluated by analysis of natural mineral water and certified reference materials.