Sensitive determination of osmium in natural waters by inductively coupled plasma mass spectrometry after photochemical vapor generation

Accurate analysis of osmium is important in geochemistry and geochronology. The current osmium analytical methods often suffer from low sensitivity, multi-step extraction, high procedural blank, and severe memory effect. In this work, a highly sensitive and simple method for the determination of osmium in natural waters was developed by coupling inductively coupled plasma-mass spectrometry with photochemical vapor generation. The procedural blank is low due to the needlessness of high concentration strong oxidant. What's more, the memory effect was successfully solved by using 5.0% ammonium hydroxide elution instead of using concentrated inorganic acid or oxidant reagent reported before. The influences of the concentration of nitric acid, the flow rate of carrier gas, the photo irradiation time on osmium detection were investigated. Under optimized conditions, the detection limit was 0.8 pg mL− 1. A precision of 3.2% (RSD, n = 5) was achieved at a concentration of 1 ng mL− 1. The accuracy is successfully validated in several natural water samples with spike recoveries from 97% to 106%. The proposed method is sensitive, simple, low blank, and memory effect-free, which has a great potential in relevant geochemistry and geochronology study.