Abstract
In connection with the previous report, the present paper deals with the application of the red fluorescence, which appears in the reaction of copper ions with thiolized thiamine, to a new qualitative analysis of copper. Cuprous ion was more sensitive to this fluorescence analysis than cupric ion.
The thiolized thiamine reagent was prepared by dissolving thiamine hydrochloride in sodium hydroxide at pH 11. The sample solution was prepared by reducing cupric ion to cuprous with hydroxylamine hydrochloride, and adjusting pH to 7. The fluorescence study was carried out on both spot test and solvent extraction methods.
In spot test analysis, a portion of sample solution was spotted on a filter paper, the thiolized thiamine reagent was then added, and the red fluorescence was measured under ultraviolet rays of 3650Å. The limit of identification was 0.3μg Cu per drop.
In the extraction method, the reaction product of cuprous-thiolized thiamine system was extracted with iso-amyl alcohol and then the intensity of the red fluorescence was also examined in the same way described above. The limit of identification of copper was 6μg per ml.
Further study showed that this red fluorescence was quite specific for copperion, and no other cations and anions except sulfide quenched the fluorescence and interfered with the detection of copper.
