The analytical method for the determination of phosphorus in foods was validated by inductively coupled plasma optical emission spectrometry (ICP-OES) in terms of precision, accuracy, recovery efficiency and linearity. Regression analysis revealed good correlation coefficient, higher than 0.999. Recovery efficiencies of the minerals ranged from 90.36% to 110.63%, and the limit of detection (LOD) and the limit of quantification (LOQ) were 0.0745 mg/ kg and 0.2482 mg/kg, respectively. The value of inter-day and intra-day ranged from 1.43 to 3.23% and from 0.40 to 1.77%. The recovery efficiencies ranged from 97.8 to 110.6%. The method was also compared with Molybdenum blue colorimetric method using certified and statistically significant difference was also not observed in the between two different analytical methods. The ICP-OES method was applied to phosphorus determination in commonly consumed foods. The obtained results suggest that the method verified in the present study may be used as an official analytical method for clear understanding of phosphorus database for national health promotion.

본 연구에서는 식품공전에 제시되어 있는 microwave digestion 전처리방법과 유도결합 플라즈마 방출분광기을 이용하여 식품 중의 9종의 무기질(Na, Ca, K, P, Mg, Fe, Cu, Mn 및 Zn)을 측정하는 분석법에 대한 직선성, 정밀성 및 정확성 등의 분석법 유효성 검증을 실시하였다. 본 연구에 사용된 표준시료는 Certificated reference material1849a 조제분유로 미국 national institute of standards & technology에서 구입하였다. 직선성은 표준품을 사용한 표준검정곡선 측정농도범위에서 상관계수 0.9999 이상의 양호한 결과를 나타내었다. 검출한계는 0.1005 mg/kg, 정량 한계는 0.3351 mg/kg 으로 각각 나타났다. 또한 정밀도는 상대적표준편차(relative standard deviation)가 일내(withinday, n=3), 반복측정의 경우 0.09~4.80%, 일간(between-day, n=12)의 경우 1.19~18.19%로 양호한 결과를 나타내었으며 정확성은 회수율 90.35-110.63%로 매우 양호한 결과를 나타내었다. 따라서 microwave 전처리방법과 유도결합 플라즈마 방출분광기 측정법은 식품 중 9종의 무기질을 측정하는데 매우 유용할 것으로 사료되며 국민 건강 증진을 위한 식품성분표 데이터베이스 구축, 유통식품의 품질평가 등 공익적 분석사업에 이용될 수 있을 것으로 생각된다.

Research has been in progress for more than a decade to production of useful proteins by genetic modification in cattle. However, the levels of protein production in transgenic cattle have been reported very low. To enhance protein production in transgenic animal, we tried homologous recombination to donor cells for production of transgenic clone cattle through nuclear transfer procedure. Thus, we constructed the two targeting vectors of human thrombopoietin (TPO) at bovine -casein locus using homologous recombination with 13.6 kb and 9.6 kb homology. In two targeting vectors, positive selection was through the neomycin resistance gene and negative selection was by the diphtheria toxin (DT). Gene targeting was attempted in bovine embryonic fibroblasts (bEF) and bovine ear skin fibroblasts (bESF). To determine the most appropriate concentration of neomycin for bEF and bESF, G4l8 resistance was confirmed by culturing the cells in various concentrations of the drug and both of the cells were optimally selected at of neomycin. The transfected bEF and bESF by the targeting vectors were colonized efficiently at the ratio of DNA to transfection reagent such as :2 and :. Comparing number of healthy clones from passage 4 to passage 8, bESF (17%) persist in culture for much longer than bEF (6%). The two gene-targeted bESF clones of 30 random-integrated clones with 9.6 kb homology length were confirmed, however, nothing was out of 72 random integration clones with 13.6 kb homology length, The DT also worked more efficiently in clones transfected with the vector of 9.6 kb homology length. Our data suggests that the choice of donor cell for long culture period should be considered to obtain targeted cell clone, and the gene-targeting frequency and the DT working efficiency are dependent on the length of target homology.