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痕量铁的催化光度法测定已有报道.试验发现,在稀硫酸介质中,痕量Fe(Ⅲ)对过氧化氢氧化苄橙的反应具有强烈的催化作用,非催化反应与催化反应的吸光度之差(△A=A_0-A_1)与Fe(Ⅲ)浓度在一定范围内呈线性关系.本法的测定范围为0～1,0μg/25ml,检出限为3.3×10~(-8)μg·ml~(-1),由此建立了痕量Fe(Ⅲ)的测定方法.本法具有重现性好,选择性很高的特点.用于人发、指甲中痕量Fe(Ⅲ)的测定,取得较好的结果.1 试验部分1.1 仪器与试剂721型分光光度计;JY-501型超级恒温槽苄橙:0.001mol·L~(-1);硫酸:1.0mol·L~(-1)过氧化氢:7.5%;α-α’联吡啶:0.1mol·L~(-1)Fe(Ⅲ)标准溶液:1μg·ml~(-1)1.2 试验方法选用刻度一致的两支具玻塞的25ml比色管,加入苄橙0.4ml,稀硫酸0.8ml,过氧化氢0.4ml,α-α’联吡啶(活化剂)1.0ml,再在其中一支中加入一定量的Fe(Ⅲ),另一支不加,两者均用水稀释至刻度,摇匀,同时放入沸水中,8min后加入异丙醇1.
Catalytic spectrophotometric determination of trace amounts of iron has been reported, and it has been found that trace amounts of Fe (III) catalyze the reaction of benzyl orange with hydrogen peroxide in dilute sulfuric acid medium. The catalytic reaction of non-catalytic reaction with the absorbance (△ A = A_0-A_1) and Fe (Ⅲ) were linear within a certain range.The determination range of this method was 0 ~ 1, 0μg / 25ml with the detection limit of 3.3 × 10 ~ (-8) μg · ml ~ (-1), the method for the determination of trace Fe (Ⅲ) was established.The method has the advantages of good reproducibility and high selectivity.It is suitable for the determination of trace Fe (Ⅲ) in human hair and nails ) Of the test, to obtain better results .1 Experimental 1.1 Instruments and reagents 721 spectrophotometer; JY-501-type super-thermostat bath orange: 0.001 mol·L -1; sulfuric acid: 1.0mol·L ~ (-1) Hydrogen peroxide: 7.5%; α-α ’bipyridine: 0.1mol·L -1 Fe (Ⅲ) standard solution: 1μg · ml -1 1.2 Test method The same scale 25ml colorimetric tube with a glass stopper, add 0.4ml of benzyl orange, dilute sulfuric acid 0.8ml, hydrogen peroxide 0.4ml, α-α ’bipyridine (activator) 1.0ml, then add a certain amount of Fe (Ⅲ), the other is not added, both diluted with water to the mark, shake, at the same time into boiling water, 8min Isopropyl alcohol 1.