본 연구에서는 ICP-DRC/MS를 이용하여 비소(arsenic) 분석의 주요 방해물질인 $^{40}Ar^{35}Cl^+$과 $^{40}Ca^{35}Cl^+$에 의한 간섭의 영향 없이 극미량의 비소를 간편하고 신속하게 측정할 수 있는 방법을 제시하였다. 즉, 반응기체로 산소($O_2$)를 dynamic reaction cell에 도입하여 플라즈마 기체 내부에서 생성된 비소이온($As^+$)과 반응시켜 $AsO^+$를 생성시킨 후 m/z=91을 검출함으로써 기존의 m/z=75($As^+$) 검출방법에 비해 우수한 재현성과 검출한계를 얻을 수 있었다. 반응기체($O_2$)의 양은 0.5 mL/min 일 때 최적조건으로 나타났으며, 검출한계는 $0.02{mu}g/L$, 정확도(RSD)는 3.4%, 회수율은 96%로 나타났다. 이 분석방법으로 서울시 한강 팔당 본류 유입 지류천에서 채취된 시료 중의 비소를 분석한 결과, $0.53{sim}1.26{mu}g/L$의 농도로 나타났으며 우수한 재현성을 나타냈다. 또한 이 방법은 다량의 염소(Cl)나 칼슘(Ca)을 함유한 해수, 식품, 하수 및 폐수 중의 비소 분석에도 유용하게 적용될 수 있으리라 기대된다.
In this investigation, an ICP-DRC/MS method to measure arsenic with ultra-trace concentration without any interference by the compounds such as $^{40}Ar^{35}Cl^+;and;^{40}Ca^{35}Cl^+$, which disturb the precise measurement of arsonic was described. Thus, the oxgen was introduced into the dynamic reaction cell as reaction gas and reacted with arsenic ion created in plasma gas, $AsO^+$ was formed and detected with m/z of 91 by ICP-MS. It resulted in better detection limit than the old method with m/z of 75($As^+$). The optimum condition for oxygen supply as the reaction gas was 0.5 mL/min. The analytical features of the method are as follows: detection limit of $0.02{mu}g/L$, precision(RSD) of 3.4%, and recovery of 96%. Arsenic in the water samples from the tributary streams to the Han River and the main stream of Paldang were analyzed with this method to identify the characteristics in its distribution. The concentration of As ranged from 0.53 to $1.26{mu}g/L$. We could measure As with very low concentration, less than $1.0{mu}g/L$, with excellent reproducibility. The method developed is expected to be applied to analyze As of the samples from sea water, food, and domestic and industrial waste water which have high concentration of Cl and/or Ca.
