Browse > Article
http://dx.doi.org/10.5806/AST.2015.28.6.460

Quantitative analysis of cholesterol in infant formula by isotope dilution liquid chromatography-tandem mass spectrometry  

Ahn, Eun Jeong (Department of chemistry, Choongnam National University)
Lee, Hwa Shim (Center for bioanalysis, Division of Metrology for Quality of Life, Korea Research Institute of Standards and Science)
Kim, Byung Joo (Center for bioanalysis, Division of Metrology for Quality of Life, Korea Research Institute of Standards and Science)
Lee, Gae Ho (Department of chemistry, Choongnam National University)
Publication Information
Analytical Science and Technology / v.28, no.6, 2015 , pp. 460-466 More about this Journal
Abstract
An isotope dilution liquid chromatography tandem mass spectrometry was developed as a primary method for the quantitative analysis of cholesterol in infant formula. Cholesterol-d4 was used as an internal standard and spiked into the infant formula sample. In order to release cholesterol out of cholesteryl ester, which is cholesterol bound to fatty acids in infant formula, saponification was carried out. Saponification conditions were optimized with heating temperature, reaction time and the concentration of KOH. The optimum conditions were as follows; heating temperature was 70 ℃, reaction time was 180 min and the concentration of KOH was 0.8 mL of 8 M KOH for about 0.1 g infant formula sample. Extraction of cholesterol out of sample solution was carried out with hexane uisng liquid-liquid extraction. Chromatographic analysis was carried out using Phenomenex Kinetex C18 column. Mobile phase was 0.1% acetic acid in methanol/water (v/v, 99/1) and flow rate was 0.3 mL/min. Cholesterol and cholesterol-d4 were monitored at mass transfer m/z 369/259 and 373/263 respectively. Reproducibility of the method was evaluated to be 0.23% of the measurement result. The expanded uncertainty of the measurement result of cholesterol in infant formula was approximately 1.9% at a 95% confidence level. NIST standard reference material having certified values of cholesterol in infant formula, was analyzed in order to verify this method. The ID-LC/MS/MS results were well agreed with the certified values of NIST SRM within the uncertainty.
Keywords
Cholesterol; Saponification; Infant formula; ID LC-MS/MS; Primary method;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 I. S. Jeong, B. M. Kwak, J. H. Ahn, D. G. Leem, T. H. Yoon, C. Y. Yoon and J. Y. Jeong, J. Food Sci., 77(10), C1042-1046 (2012).   DOI
2 D. J. Fletouris, N. A. Botsogloi, L. E. Psomas and A. I. Mantis, J. Dairy Sci., 81, 2833-2840 (1998).   DOI
3 J. M. Kim, J. M. park, T. H. Yun, D. G. Lim, C. Y. Yun, J. Y. Jung, I. S. Jung, B. M. Kwak and J. H. Ahn, Korean J. Food Sci. Ani. Resour., 31(6), 944-951 (2011).   DOI
4 Korea Food Code, 10.1.1.5.6, Cholesterol, Korea Food Industry Association, Seoul, Korea, 431-433 (2010).
5 B. H. Ryu, Cholesterol and Atherosclerosis, Shinji Press, Busan (1998).
6 J. P. Sweeney and J. L. Weihrauch, CRC Crit. Rev. Food Sci. Nutr., 8, 131-159 (1976).   DOI
7 K. MichiHiroshi and I. Katsumi, Cholesterol, Shinkwang Press, Seoul (1990).
8 ISO guide 98-3, “Guide to the Expression of Uncertainty in Measurement (GUM: 1995)” (2010)
9 KRISS Publication, "Improvement of Measurement Accuracy for Amount of Substance" (1999).
10 H. S. Lee, Quantifications of amino acids in human serum by isotope dilution liquid chromatography/tandem mass spectrometry, Chungnam National University, Graduate school, T1TB4, 007-8 (2007).
11 M. Rychlik and S. Asam, Anal Bioanal. Chem., 390, 617-628 (2008).   DOI
12 P. Ellerbe, S. Meiselman, L. T. Sniegoski, M. J. Welch and E. White, Anal. Chem., 61, 1718-1723 (1989).   DOI
13 M. Marlier, G. Lognay, J. Wagstaffe, P. Dreze and M. Severin, Fresenius J Anal Chem., 338, 419-422 (1990).   DOI
14 B. Zhonging, X. Rongnian, Z. Jinhua, China dairy industry, 27, 1 (1999).
15 M. Fenton, J. Chrom., 624, 369-388 (1992).   DOI
16 D. K. Lee, J. H. Ahn and H. S. Kwak, Food Biotechnol, 6, 322-324 (1997).