萃取-紫外分光光度法测定显影液中的米吐尔和对苯二酚

Determination of amount of metol and p-hydroquinone in developing solution by UV-spectrophotometry

本文选择在波长 2 5 2nm和 2 95nm处测定冲洗黑白航空胶片的显影液中的米吐尔和对苯二酚的乙酸乙酯萃取液。米吐尔的含量可以直接测得 ,对苯二酚的结果要通过简单计算求得。本法简便、灵敏、相当可靠。波长 2 5 2nm略低于乙酸乙酯的截止波长 2 6 0nm 。

The proposed method for the determination of amount of metol and p-hydroquinone is based on their absorption at 252 and 295nm,respectively. Deve-loping solution containing both compounds couldbe measured at 252 and 295nm after extractinwith ethyl acetate. The result of Metol could be read out directly and that of the hydroquinone calculated by means of two improvised equations.Extraction has been proved to be necessary by The fact that the two compounds in the developing solution of films are rather unstable.meanwhile,extration can also eliminate interferences, Such as sulfonates of the developers and the Protecting agent sodium sulfite added.