HPLC柱后衍生法测定食盐中的IO_3^-  

Determination of Iodate in Salt Using HPLC with Post-column Derivation

作　　者：张自禄[1] 周国庆[1] 马越[1] 黄萍[1] 

机构地区：[1]西北核技术研究所,西安710024

出　　处：《中国调味品》2016年第1期136-139,共4页China Condiment

摘　　要：利用1mol IO_3^-在酸性条件下与I^-生成3mol具有较大摩尔吸光系数I-3的反应建立了测定碘盐中IO_3^-含量的HPLC-UV柱后衍生方法。采用Hamilton PRP-X100阴离子交换柱(Φ4.6×250mm)做分析柱、1mol/L NaCl做流动相、KI与HCl混合溶液做柱后衍生试剂,在流动相和柱后衍生试剂流速均为1mL/L条件下IO_3^-的保留时间为3.5min,50μL进样体积时的标准曲线拟合方程为A=6.36×10-2+0.469×C(μg/g,以I计),r2=0.99977,与不采用柱后衍生而直接测定IO_3^-在220nm吸光度的方法相比,灵敏度提高近30倍。通过测定标准碘盐样品中的碘含量对方法进行了验证,测定结果与标准值偏差小于1.7%。用所建立的方法分析了市场上购买的碘盐商品中IO_3^-的含量,结果与标称值一致。方法的最小检出限为0.18μg/g。A method is developed to determine iodate in salt using HPLC-UV with post-column derivation based on I3- with high molar absorption coefficient produced via the reaction of IO-3 and I in acid. A Hamilton PRP-X100 anion exchange resin column （04. 6×250 mm） is used as analytical column and 1 mol/L NaC1 as mobile phase. The mixture solution of KI and HC1 is used as post-column derivation reagent. When the flow rate of mobile phase and post-column derivation reagent is 1 mL/L, the retention time of IO3- is 3.5 min. The standard curve for the method with the injection volume of 50 μL is obtained and the regression equation is A= 6.36 × 10-2 ＋0. 469 × C （μg/g for I） with r2= 0. 99977. Comparatively, for the method to monitor the absorbance of iodate at 220 nm directly, the method with post-column derivation has a higher sensitivity. The method is validated by analysis of iodate in standard salt and the bias between content determined and standard value is less than 1.7%. A kind of commercial salt samples is analyzed and the content of iodate is according with the declared value. The minimum detectable limit for the method is 0.18μ g/g.

关 键 词：食盐 IO3- HPLC-UV 柱后衍生 I3- 

分 类 号：TS365[轻工技术与工程]