比色法检测婴幼儿食品中总碘的研究

<正> 碘是人体必需营养元素之一。成年人缺碘会导致甲状腺机能亢进,患大脖子病,婴幼儿缺碘会导致甲状腺发育不全,生长发育迟缓,智力低下,甚至痴呆。美国膳食允许量委员会、国家科学研究委员会推荐成人每天需碘量为150微克,儿童为70～120微克。但过量的碘会抑制甲状腺素的合成与释放,也会引起一些健康问题,因此医学上建议成人每天摄碘量

Determination of Total iodine in Infant Foods by Colorimetry Method

Iodine commonly present in infant foods may be the form of the organically bound iodine and freely inorganic iodine. In our study a simple method tor the determinatio of total iodine in food, based on the catalytic destruction of thiocyanate by nitrite in the presence of iodine, have been evaluated. Alkaline dry ashing has been used for the destruction of organic matter and the liberation of iodine, in which use of protassium carbonate to fix iodine and use of zinc sulphate as ashing aid. Critical parameters of the colorimetric reaction are strictly controlled. Finally measure the colour intensity at a wavelength of 450nm on Spectrophotometer at exactly time intervals. The detection limit of this method is approximately 1 ng (5ppb); the precision of iodine determina-ti on is 2.74±0.13ppm (C.V. 4.7%), 1.02±0.045ppm (c.v. 4.4%); 0.084±0.0073ppm (c.v. 8.6%); the recovery of added iodine is 100.1±4.,4%; 103.4±5.3%; 97.9±5.7%; results for the total iodine in NBS reference materials determined by suggested method showed satisfactory agreement with the certified values. This method can be widely used for the determination of total iodine in various foods.