PDF《Soy- and Milk-Based Infant Formulas》

Determination of Iodide and Iodate in Soy- and Milk-Based Infant Formulas Lipika Basumallick and Jeffrey Rohrer Thermo Fisher Scientific, Sunnyvale, CA, USA Appl i ca t i o n No te

3 7 Key Words Ion Chromatography (IC), Pulsed Amperometric Detection (PAD), Silver Working Electrode, Nutrition, Thiocyanate Introduction Iodine is an important micronutrient essential for the production of thyroid hormones that are involved in the regulation of many key biochemical reactions.

1 Iodine deficiency can lead to varying degrees of growth and developmental abnormalities in children and adults, including such illnesses as goiter and cretinism.2 However, an excess of iodine can also lead to thyroid disorders, especially in infants.3 As iodine is primarily absorbed from our diet, supplementation of iodine in food is a common practice.4 The concentration of iodine in iodine-fortified foods is often regulated and monitored. Infant formula is the most highly regulated consumer food product on the market today. The Infant Formula Act of

1980 specifies minimum and maximum amounts of several nutrients, and authorizes the U.S. FDA to create and enforce standards for commercial infant formulas. Based on the recommended dietary intake of iodine, infant formulas should have a minimum iodine concentration of

5 μg/100 kcal and no more than

75 μg/100 kcal.5,6 Accurate measurement of iodine in food matrices requires: (i) a robust iodine extraction method;

and (ii) a sensitive analytical method for iodine quantification. Analytical methods that have been used for determining iodine in food matrices include: colorimetry based on catalytic reactions,7 gas chromatography,8 an ion-selective electrode method,9 x-ray fluorescence spectrometry,10 inductively coupled plasma-mass spectrometry/optical emission spectrometry (ICP-MS/OES),9,11,12 radiochemical neutron activation analysis,13 IC with UV detection,14 electrochemical detection15C17 , cathode stripping voltam- metry,18 and flame atomic absorption spectrometry.19 A few of these have been adopted as official methods: (i) AOAC Method 992.24, Iodine in Ready-to-Feed Milk- Based Infant Formula―Ion-Selective Electrode Method;

20 (ii) LMBG 49.00-6, the German Food Law'

s method for total iodine by ICP-MS (also sanctioned as the British- adopted European Standard for Determination of Iodine by ICP-MS as BS EN15111:2007);

22 and (iii) Determina- tion of Iodide Content in Milk and Dried Milk Method Using High Performance Liquid Chromatography, BS ISO 14378:2000. A number of iodine extraction methods have also been developed for milk and milk-based products―microwave digestion in open or closed vessels with perchloric acid/ nitric acid/tetramethyl ammonium hydroxide, oxygen combustion, alkaline extraction, acid digestion (hydrochloric acid/acetic acid), precipitation with metha- nol/acetonitrile, and ultracentrifugation.14,15,22,24 Please note that methods using perchloric acid and/or pressurized chambers can pose a safety risk. Application Note C_IC-076 关键词 氯离子;

硝酸根离子;

磷酸根离子;

柠檬酸根离子;

阴离子电导检测;

质谱 检测;

离子色谱 目标 基于母乳中无机盐离子对婴幼儿的体液平衡的影响,本文欲通过离子色谱- 抑制电导检测和质谱确认,建立一种快速、灵敏测定母乳中无机阴离子的方 法. 母乳中氯离子和硝酸根离子含量的测定 廖冬丽 陈静 许群 赛默飞世尔科技(中国)有限公司 引言 母乳和婴幼儿乳制品中的微量元素是对婴幼儿身体健 康有着重要作用.但如果长期食用含钠、钾、钙、镁、氯 等离子过高的母乳或奶粉,会打破婴幼儿体液的正常平 衡,导致肾脏负荷加重,甚至会危害心血管系统.[1,2] 因此,阴离子如氯、硝酸根等离子的添加量也是影响乳制品 质量的重要指标;