动力学分光光度法测定食品中的痕量铁

KINETIC SPECTROPHOTOMETRIC DETERMINATION OF TRACE Fe() IN FOOD SAMPLES

介绍了一种动力学分光光度测定痕量铁的方法。在ｐＨ＝４．７０的ＨＡｃＮａＡｃ介质中，Ｆｅ（Ⅲ）对Ｈ２Ｏ２氧化番红花Ｔ的反应具有强烈的催化作用，使溶液颜色褪去。该溶液最大吸收波长为５２０ｎｍ，铁含量在３．０８×１０６２．８０×１０５ｇ／Ｌ范围内遵从比尔定律，表观摩尔吸光系数为５．６×１０５Ｌ·ｍｏｌ１·ｃｍ１，回归方程为：ΔＡ＝５．６×１０５ＣＦｅ（Ⅲ）＋０．０２（Ｃ的单位为ｍｏｌ·Ｌ１），相关系数γ＝０．９９９９，检出限为３．１６×１０６ｇ／Ｌ，同时也研究了多种干扰离子对测定的影响，该方法应用于测定食品如大米。

A new method is described for spectrophotometric determination of trace iron, based on the oxidation of safranm T with hydrogen peroxide, using iron() as catalyst. The reaction solution has a maximum absorption in 520 nm. Beers law is obeyed in the range of 3.0810\+\{-6\} to 2.8010\+\{-5\} g iron() per liter. The apparent molar absorptivity is 5.610\+5 Lmol\+\{-1\}cm\+\{-1\}. The linear regression equation is A=5.610\+5 \%C\%\-\{Fe()\}+0.02, with a linear correlation coefficient of 0.9999. The detection limit of trace iron is 3.1610\+\{-6\} g/L. Effect of coexisting ions on determination of iron and elimination of interference of some metal ions was studied. Satisfactory results have been achieved for determination of trace iron in food samples such as rice and flour.\=WTHZ]