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A wide variety of organic acids can be titrated in acetone using a tetraalklylammonium hydroxide in benzenemethanol as the titrant.

oxidation is not necessary for the full recovery of arsenic from animal tissue (6). However, when hydrochloric acid digestion of animal tissue was carried out in an open vessel, the recovery of arsenic was always low. The modified digestion apparatus (9) permits tissue solution while maintaining an upper internal temperature below the volatilization point of arsenic trioxide (2) and arsenic trichloride (10). Kingsley and Schaffert (6) found that when reflux was used during the tissue digestion, less than 50% of the added arsenic was recovered because of the retention of hydrogen sulfide and other mercapto (-SH) groups in tissue which combined with arsenic and prevented its distillation. The concentration of mercapto groups in 1 gram of tissue is too low in relation to the amounts of arsenic detectable by this method to produce 339 (1944).

In acid solution a column of activated alumina will retain sulfate more readily than most other anions. It is therefore possible to separate as little as 0.5 p.p.m. sulfate from large