건강기능식품에서 이산화규소 분석 방법을 확립하기 위하여 산(불산과 붕산)분해를 이용한 ICP-OES 방법을 수행하였다. 이 방법의 검출한계와 정량한계는 각각 0.07 mg/ L, 0.20 mg/L 이었다. 검량선은 0.2~20.0 mg/L의 농도범위 에서 우수한 직선성(r2 0.99)을 보였다. 글루코사민 제품에 이산화규소 0.4, 1.0, 2.0% (w/w)를 첨가하여 시험한 결과 90.22~94.14%의 회수율과 0.72~1.67%의 정밀성을 나타내었다. 확립된 방법으로 시중에 유통되는 건강기능식품 11 품목의 이산화규소 함량을 분석한 결과 0.02~1.80% (w/w) 로 나타났다. 이 결과는 건강기능식품에 이산화규소의 사 용기준 2% (w/w) 이하를 만족하는 결과로 시험한 제품들 은 규격에 적합하였다. 따라서 본 연구에서 확립된 이 방법은 건강기능식품 중 이산화규소를 쉽고, 빠르게 분석할 수 있으며, 건강기능식품 중 이산화규소 함량 분석에 효율 적으로 사용될 수 있다

We demonstrated the sensitivity of optically active single-walled carbon nanotubes (SWCNTs) with a diameter below 1 nm that were homogeneously dispersed in cement composites under a mechanical load. Deoxyribonucleic acid (DNA) was selected as the dispersing agent to achieve a homogeneous dispersion of SWCNTs in an aqueous solution, and the dispersion state of the SWCNTs were characterized using various optical tools. It was found that the addition of a large amount of DNA prohibited the structural evolution of calcium hydroxide and calcium silicate hydrate. Based on the in-situ Raman and X-ray diffraction studies, it was evident that hydrophilic functional groups within the DNA strongly retarded the hydration reaction. The optimum amount of DNA with respect to the cement was found to be 0.05 wt%. The strong Raman signals coming from the SWCNTs entrapped in the cement composites enabled us to understand their dispersion state within the cement as well as their interfacial interaction. The G and G’ bands of the SWCNTs sensitively varied under mechanical compression. Our results indicate that an extremely small amount of SWCNTs can be used as an optical strain sensor if they are homogeneously dispersed within cement composites.