食用油中过氧化值的测定 应用资料

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食用油中过氧化值的测定 应用资料制备的油脂试样溶解在异辛烷和冰乙酸中，试样中过氧化物与碘化钾反应生成碘，反应后用硫代硫酸钠标准溶液滴定析出的碘，用电位滴定仪确定滴定终点。用过氧化物相当于碘的质量分数或1kg样品中活性氧的毫摩尔数表示过氧化值的量。TIB-97003enL KGM KYOTO ELECTRONICS MANUFACTURING CO.，LTD. Application Memo POV of Cooking Oil Industry Fat and Oil Instrument Automatic potentiometric titrator Measurement method Redox titration Standards The JOCS Standard methods for the Analysis of Fats， Oils and Related Materials ISO 3960， GB 5009.227 1.Overview Peroxide value is determined according to the above standards. Dissolve the cooking oil sample i n the mixture of chloroform and acetic acid (1+2) solution while removing the dissolved oxygen by flowing nitrogen gas . After adding potassium iodide and pure water to the sample， free iodine is t i trated with 0.01mol/L sodium thiosulfate. The endpoint is the maximum inflexion on the titration curve. Peroxide value is calculated from the titration volume of sodium thiosulfate. 2. Apparatus Main unit Automatic potentiometric t itrator (preamplifier STD) Electrode Combined platinum electrode Ceramic reference electrode 3. Reagents Titrant 0.01mol/L sodium thiosulfate Solvent Chloroform and acetic acid (1+2) solution， Pure water Additive Saturated potassium iodide Inactive gas Nitrogen gas —Measurement results一 Sample Titer POV (g) (mL) (meq/kg) 1 10.0185 0.8453 0.8437 2 10.0310 0.8655 0.8628 3 10.0382 0.8736 0.8703 Average 0.8590 SD 0.0137 RSD(%) 1.59 -Titration curve一 Please feel free to contact us for any further information. Kyoto Electronics Manufacturing Co.， Ltd.Overseas Sales & Market i ng Sect. 京都电子工业株式会社-可睦电子(上海)商贸有限公司 上海市徐汇区宜山路333号1201室 电话：021-54488867 电邮： kemu-kem@163.com 网址： http：//www.kem-china.com