Determination of Selenium in Milk by ICP-OES

ICP-OES를 이용한 우유의 Selenium 분석

  • 김효중 ((주)한국야쿠르트 중앙연구소) ;
  • 박종길 ((주)한국야쿠르트 중앙연구소) ;
  • 신정걸 ((주)한국야쿠르트 중앙연구소) ;
  • 백영진 ((주)한국야쿠르트 중앙연구소)
  • Published : 2003.12.01

Abstract

The purpose of this paper was to determine the quantity of selenium in milk by inductively coupled plasma optical emission spectrometry. The sample was digested in teflon vessel containing nitric-hydrogen peroxide acid mixture. After digestion, the sample is treated with additional hydrochloric acid. Total selenium was reduced with sodium borohydride and concentrated hydrochloric acid in a simplified hydride generation(HG) manifold. The optimum conditions of HG are 2 M for HCl, 1.5% for NaBH$_4$, 1.2 mL/mim for sample flow. Recovery rates by the standard addition method were 88.0% at 10 ppb and 92.2% at 10 ppm. The relative standard deviations were 4.8 and 3.2%, respectively. This method showed a good accuracy and precision. And so it was highly suitable for determination of small quantity of selenium in milk.

우유의 셀렌 함량을 측정하기 위하여 ICP-OES를 이용한 분석법을 확립하였다. 시료전처리는 우유의 수분을 제거한 후 질산과 과산화수소를 이용하여 유기성분을 제거하였고, 최종적으로 다시 과산화수소로 미량의 유기성분을 산화시켰다. 셀렌은 휘발성 무기성분이므로 전처리된 용액에 NaBH$_4$와 HCl을 이용하여 셀렌의 수소화(hydride)반응으로 끓는점을 높이고 분석감도를 향상시켰다. 수소화 반응 중 HCl 농도의 최적조건은 2 mol/L에서 최대 cps(counter per sec)로 나타났고, NaBH$_4$와 시료 유속의 최적조건은 각각 1.5%와 1.2mL/min인 것으로 나타났다. 따라서 위의 HG 조건이 시료 메트릭스에 따른 간섭효과를 제거하였으며, 최적의 정량조건임을 알 수 있었다. 이 조건으로 표준물질을 이용한 셀렌의 직선성 상관계수(R)는 0.98로서 우유에 함유된 셀렌 분석에 적용할 수 있었다. Standard addition method를 이용한 회수율은 10 ppb에서 88.0% 이었고, 첨가된 농도가 증가할수록 회수율 및 RSD는 정확성 및 정밀성을 확보할 수 있었다.

Keywords

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