National Institute of Standards and Technology における超伝導研究及び生活

Food and feed laboratories share several similarities when facing the implementation of liquid-chromatographic analysis. Using the experience acquired over the years, through application chemistry in food and feed research, selected analytes of relevance for both areas were discussed. This review focused on the common obstacles and peculiarities that each analyte offers (during the sample treatment or the chromatographic separation) throughout the implementation of said methods. A brief description of the techniques which we considered to be more pertinent, commonly used to assay such analytes is provided, including approaches using commonly available detectors (especially in starter labs) as well as mass detection. This manuscript consists of three sections: feed analysis (as the start of the food chain); food destined for human consumption determinations (the end of the food chain); and finally, assays shared by either matrices or laboratories. Analytes discussed consist of both those considered undesirable substances, contaminants, additives, and those related to nutritional quality. Our review is comprised of the examination of polyphenols, capsaicinoids, theobromine and caffeine, cholesterol, mycotoxins, antibiotics, amino acids, triphenylmethane dyes, nitrates/nitrites, ethanol soluble carbohydrates/sugars, organic acids, carotenoids, hydro and liposoluble vitamins. All analytes are currently assayed in our laboratories.

Liquid Chromatography Analysis of Common Nutritional Components, in Feed and Food.

Determination of toxic heavy metals and speciation of arsenic in seaweeds from South Korea

Natural variation of selenium in Brazil nuts and soils from the Amazon region

Determination of minor and trace elements in aromatic spices by micro-wave assisted digestion and inductively coupled plasma-mass spectrometry

Method validation for simultaneous determination of chromium, molybdenum and selenium in infant formulas by ICP-OES and ICP-MS

The objective of this study was to develop a method to simultaneously quantify vitamins A and E in infant formula. To determine the vitamin A and E content, vitamin A and four different vitamin E isomers (α-, β-, γ-, and δ-tocopherol) were separated by high performance liquid chromatography with a photodiode array detector using a Develosil RPAQUEOUS RP-C column (4.6×250 mm, 5 µm). The vitamin A and E contents in the certified reference material determined using this method were within the certified range of standard values. The limits of detection (LODs) and limits of quantitation (LOQs) for vitamin A were 0.02 and 0.06 µg/L, respectively. LODs and LOQs for the vitamin E isomers ranged from 0.20 to 0.55 and from 0.67 to 1.81 µg/L, respectively. Linear analyses indicated that the square of the correlation coefficient for the vitamin A and E isomers was 0.9997–0.9999. The recovery of vitamins ranged from 96.69 to 97.79%. The results demonstrate that this novel method could be used to reliably analyze vitamin A and E content in infant formula.

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Simultaneous Determination of Vitamin A and E in Infant Formula by HPLC with Photodiode Array Detection

본 연구에서는 조제분유 중의 콜레스테롤을 신속하고 정확하게 분석하기 위해 지방 추출 과정을 거치지 않는 직접 검화 방법을 선택하여 분석법 개발을 시도하였다. 조제분유 분말시료를 직접 검화 수기에 취하여 검화 온도, 검화 시간, KOH 농도의 3가지 인자에 대해 콜레스테롤 회수율이 가장 양호하게 나타나는 최적 검화조건을 확립하고, 검화 후 수세과정에서 액액 분배가 용이한 용매 조건도 확립하였다. 또한 콜레스테롤 피크의 완전한 분리를 위한 적정 기기 조건을 확립하였다. 그 결과, 시료 약 2 g에 16 M-KOH 10 mL를 넣고 90℃에서 60분 가열하여 검화한 후 diethyl ether로 3회 추출하고 hexane을 최종시험 용액으로 하여 기기분석을 했을 때의 회수율이 98.80%로서 가장 양호하게 나타났다. 본 연구를 통해 개발된 조제분유의 효율적인 액액분배 및 직접가열 검화법은 일원배치 분산법에 의해 유화가공식품의 콜레스테롤 분석법으로 유효성이 검증되었으며, 아울러 개발된 전처리 방법 및 기기 분석 조건을 활용해 다양한 분석 기관에서 신속 정확하고 효율적인 콜레스테롤 분석을 수행할 수 있을 것으로 기대된다. 또한 산업체의 품질관리 및 검증기관에서 필요시 모니터링에 적극 활용 가능할 것으로 사료되며, 이를 통해 유화가공식품 류의 함량표시 및 규격관리의 정확성과 효율성 증대에 기여하여 제조업체의 정확하고도 효과적인 품질 및 안전성 확보에 기여할 수 있을 것으로 판단된다. 특히 위해 물질에 대한 정확한 함량 판단이 중요한조제분유 등의 영·유아용 식품의 안전성 확보에 지대한 공헌을 할 수 있을 것으로 기대된다.

/pdf/development-of-analysis-method-for-cholesterol-in-infant-48igrxtfyu.pdf

Development of Analysis Method for Cholesterol in Infant Formula by Direct Saponification

This study intented to standardize the method for total polysaccharide, which is a functional marker for aloe vera gel in Korea. We used four lyophilized raw materials and commercial aloe gel products, certified as Health Functional Food by Korea Food and Drug Administration, including powder, solution, jelly, tablet and cap- sule, to optimize the analytical condition of dialysis and phenol-sulfuric acid reaction in polysaccharide analysis. The optimal conditions for polysaccharide analysis included 1 L water for dialysis and change 3 times for 24hr against 25 mL prepared sample solution. Validation test showed lower than 5% of coefficient of variation(CV) in intra-, inter- day validation in lyophilized raw materials and 4 types of commercial products. In inter-person and inter-laboratory validation with 4 persons from 4 different laboratories, CV(%) were 5.50 and 6.64 respectively. The linearity of polysaccharide analysis was assessed using 5 serial concentration of lyophilized raw materials(0.1, 0.2, 0.3, 0.4, 0.5%(w/v)). The results showed R 2 ≥ 0.995 of high linearity. In the commercial aloe vera gel products, the results of reproductivity showed lower than 7.08% and revealed that the standardized method from this study ensured high pre- cision for polysaccharide analysis.

/pdf/improvement-of-analytical-method-for-total-polysaccharides-3g9kxl93ib.pdf

Improvement of Analytical Method for Total Polysaccharides in Aloe vera Gel

This study was carried out to develop an analytical method for the determination of vitamin D in infant formula. Vitamin D was determined by column-switching high-performance liquid chromatography (HPLC) equipped with a reversed phase column and UV detector after saponification and extraction of the formula with an organic solvent. A preseparation column (C8), focusing column (C18), analytical column (C18) and UV-Vis detector (254 nm) were used. The limits of detection (LOD) and the limits of quantification (LOQ) for vitamin D were estimated to be 1.51 µg/kg and 4.95 µg/kg, respectively. The linearity, recovery, precision and accuracy of the analytical method for vitamin D were evaluated through the application of a SRM (Standard Reference Material) 1846 (National Institute of Standard & Technology, USA). The linearity of this method was calculated with a value of the coefficient of determination (r 2 ) ≥0.9999. The recovery of vitamin D was 85.20±3.00%. The intra-assay precision for vitamin D was between 1.68±0.03% and 5.75±0.33%, and the inter-assay precision for vitamin D ranged from 1.73±0.03% to 2.96±0.09%. The intra-assay accuracy for vitamin D was between 100.03±2.77% and 102.01±0.59%, and the inter-assay accuracy for vitamin D ranged from 99.00±1.53% to 102.01±3.04%. The proposed method is optimal for the separation and quantification of vitamin D from infant formula.

/pdf/development-of-vitamin-d-determination-in-infant-formula-by-3eozpuz8vc.pdf

Taehyung Yoon

Papers

Method validation for simultaneous determination of chromium, molybdenum and selenium in infant formulas by ICP-OES and ICP-MS

Simultaneous Determination of Vitamin A and E in Infant Formula by HPLC with Photodiode Array Detection

Development of Analysis Method for Cholesterol in Infant Formula by Direct Saponification

Improvement of Analytical Method for Total Polysaccharides in Aloe vera Gel

Development of Vitamin D Determination in Infant Formula by Column-Switching HPLC with UV Detector