邻二氮菲比色法测雕白块的含量

PHOTOMETRIC DETERMINATION OF RONGALITE WITH 1,10-PHENANTHROLINE

雕白块是一种有毒物质。利用雕白块的还原性,可将高铁离子还原为亚铁离子,用邻二氮菲比色法进行测定。方法不需要蒸馏,具有简便快速的特点,灵敏度高,表观摩尔吸光系数为2.05×104L·mol-1·cm-1,可测出相当于0.015mg·L-1甲醛含量的雕白块。

Based on its reducing property, rongalite (or named chemically as formaldehyde sodium sulfoxylate, CH2OHSO2Na·2H2O) was determined by the reaction with Fe(Ⅲ) and 1,10-phenanthroline in an acetate buffer medium of pH 5. A definite amount of Fe(Ⅲ) ion which is equivalent to the amount of rongalite in sample was reduced to Fe (Ⅱ) and reacted with 1, 10-phenanthroline to give an orange-red complex having its absorption maxima at 510 nm. The sample solution can be directly analyzed without distillation pretreatment. As low as 0. 015 mg·L-1 of rongalite can be determined by this method.