Gu X, Chen C, Thou T
Department of Chemistry, Capital Normal University, 100037, Beijing, People's Republic of China.
Anal Bioanal Chem. 1996 Apr;355(1):94-5. doi: 10.1007/s0021663550094.
A solvent-soluble membrane filter is proposed for the simple and rapid preconcentration and spectrophotometric determination of ascorbic acid based on the reduction of 1, 10-phenanthroline (phen)-iron (III), which is collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of tri,phen-iron (II) [ferroin, Fe(phen)(2+)(3)] with an anionic surfactant (of dodecyl sulfate). The ion-associate collected is dissolved in a small volume of 2-methoxyethanol together with the filter. The colour intensity is measured at 510 nm against the reagent blank and is proportional to the content of ascorbic acid in the range 2.5-50 microg ascorbic acid in 5 ml of solvent with excellent reproducibility (RSD 3.2% for 200 microg 1(-1) ascorbic acid), the enrichment factor achieves 100-fold and detection limits better than 2.0 microg 1(-1) can be obtained. Diverse components of organic and inorganic compounds normally present in fruits, vegetable, beverages and urine do not interfere. The recoveries of the ascorbic acid added to the samples are quantitative.
提出了一种溶剂可溶性膜滤器，用于基于1,10 - 菲啰啉（phen）-铁（III）的还原对维生素C进行简单快速的预富集和分光光度测定，该离子缔合物以三（phen）-铁（II）[亚铁菲啰啉，Fe（phen）(2+)(3)]的阳离子络合物与阴离子表面活性剂（十二烷基硫酸盐）在硝酸纤维素膜滤器上收集。收集的离子缔合物与滤器一起溶解在少量的2 - 甲氧基乙醇中。以试剂空白为参比，在510 nm处测量吸光度，其与5 ml溶剂中2.5 - 50 μg维生素C的含量成正比，重现性良好（200 μg l(-1)维生素C时的相对标准偏差为3.2%），富集倍数达到100倍，检测限优于2.0 μg l(-1)。水果、蔬菜、饮料和尿液中通常存在的各种有机和无机化合物成分不产生干扰。添加到样品中的维生素C回收率是定量的。
