摘要：Arsenic dissolved from the Kjeldahl flask is a very cumbersome problem in the arsenic determination. When new Kjeldahl flasks for arsenic determination were heated with the mixture of sulfuric acid and nitric acid, the considerable amounts of arsenic were detected in these acid solutions. After washing of flasks with various kinds of acid or alkali, the amounts of arsenic dissolved from flasks were determined. As a result of experiments, it was proved that a new Kjeldahl flask should be washed for four or five times, before use, by heating with sulfuric acid and nitric acid. Boiling with sodium carbonate solution was found to be the more effective washing method.
