Iron and copper ions-synergistically enhanced cobalt photochemical vapor generation for its sensitive detection by inductively coupled plasma mass spectrometry

A novel photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometric (ICP-MS) method was proposed for the sensitive determination of trace cobalt. A synergistic enhancement effect of Fe(II) and Cu(II) ions on the PVG of cobalt was discovered in this work. The critical factors influencing the PVG process, including the reaction medium, the UV irradiation time, and the flow rate of carrier gas were investigated in detail; and the interference of the coexisting ions was also studied. The analytical sensitivity of this method increased by about 16-fold in comparison with that of the PVG without sensitizers, and the limit of detection (LOD) for cobalt was found to be 2 ng L −1 . The possible photocatalytic mechanism of the photochemical reaction was initially explored through experimental studies. The method was successfully applied to the direct analysis of seven real water samples for trace cobalt, showing analytical results consistent with those by pneumatic nebulization (PN)-ICP-MS and achieving spike recoveries of 97–113 %. The findings of this study would extend the application scope of PVG technique.