Abstract
It is possible to determine arsenic in common salt by Gutzeit method, but this method has some defects from the points of operation and reproducibility. Therefore, few reports have been found on the determination of arsenic contained in common salt. The present study was conducted on a spectrophotometric determination with silver diethyldithiocarbamate.
The recommended method was follows: Arsenic in sample solution is distilled by a method which is almost the same as the Gutzeit, and generated gas is absorbed in silver diethyldithiocarbamatepyridine solution (0.2%), and the arsenic is determined by measuring the absorbance of this solution at 535mμ. A micro amount of arsenic is determined after collection by coprecipitation with ferric hydroxide at pH 3-4.
This method was not influenced by diverse ions found in most common salt, and the repeatability was shown below ±0.1μg. Moreover, the operation was more simple and quickly done than other methods. Thid method was also applied to the determination of arsenic in sea water and bitttern, and good results were obtained.
The results showed that arsenic was contained by 0-31μg/kg in some kinds of common salt. The transference of arsenic caused due to the concentration of sea water at the boiling point was presumed that greater part was evaporated, smaller part was transferred to scale and sail, and arsenic was hardly transferred to bittern.
