碘-淀粉体系褪色光度法检测美白霜中对苯二酚

Determination of hydroquinone in Whitening Creams by fading spectrophotometry with iodine-starch system

建立了基于碘-淀粉体系的褪色分光光度法,用于检测美白霜中对苯二酚的含量。碘能被捕获到直链淀粉螺旋状结构中,形成碘-淀粉蓝色复合物,在波长578 nm有最大吸收峰。当存在对苯二酚时,碘和对苯二酚发生氧化还原反应,碘被还原为碘离子,碘-淀粉体系蓝色变浅。建立波长578 nm的吸光度降低值与浓度的线性关系,确定对苯二酚的含量和检出限。对反应条件进行了优化,结果表明,在最佳实验条件(反应介质pH为2,氧化还原反应时间为30 min, 1×10^(-3) mol·L^(-1)碘标准溶液用量为0.8 mL,0.5%淀粉溶液用量为1.0 mL)下,所建立的方法检测对苯二酚灵敏度良好:检测限为0.35 mg·L^(-1),线性范围为0.5~4.5 mg·L^(-1)。该方法可用于美白霜中对苯二酚的快速测定,检测结果与文献报道的方法一致。

A Fading Spectrophotometric method based on iodine-starch system was established for the determination of hydroquinone in whitening creams.Iodine could be trapped in the helical structure of amylose to form iodine-starch blue complex with a maximum absorption peak at 578 nm.In the presence of hydroquinone oxidation-reduction reaction occurred between iodine and hydroquinone,iodine was reduced to iodide,and the blue of iodine-starch system turned lighter.The linear relationship between absorbance reduction at 578 nm and concentration was established to determine the content and detection limit of hydroquinone.The reaction conditions were optimized,and the results showed that under the optimum experimental conditions(pH of reaction medium was 2,redox reaction time was 30 min,the dosage of 1×10^(-3) mol·L^(-1) iodine standard solution was 0.8 mL and the dosage of 0.5%starch solution was 1.0 mL),the established method has good sensitivity for the detection of hydroquinone:the detection limit is 0.35 mg·L^(-1) and the linear range is 0.5~4.5 mg·L^(-1).The method could be used for the rapid determination of hydroquinone in whitening creams,and the detection results were consistent with those reported in the literature.