Ultrasonic Mist Generation Assist Argon–Nitrogen Mix Gas Effect on Radioactive Strontium Quantification by Online Solid-Phase Extraction with Inductively Coupled Plasma Mass Spectrometry

Abstract

The Ar–N₂ mix gas effect can easily improve the sensitivity of ICPMS; however, this effect discriminates against Sr. In this study, it was found that Ar–N₂ mixed gases introduced into nebulizing gas enhanced the sensitivity of online solid-phase extraction (SPE) with inductively coupled plasma mass spectrometry (ICPMS) for radioactive strontium quantification. An ultrasonic nebulizer (USN) improved the Ar–N₂ mixture gases effect of Sr and the mix gases (with USN) enhanced 3.7-times the signal intensity of Sr in normal pure Ar gas (with USN) in an online SPE-ICPMS. By adapting the gas-loading means from a nebulizing gas unit via USN, no careful tuning was necessary for the plasma turning. With this signal enhancement, a 0.06 pg/L detection limit (0.3 Bq/L) was achieved for radioactive strontium (⁹⁰Sr) in online SPE-ICPMS within 30 min. In addition, environmental paddle water in the Fukushima Nuclear Power Plant was measured and the valued correspond to that obtained by radiometry.