A titrimetric method for the micro-determination of barium

THE preparation and purification of substances of biological interest is in many cases facilitated through their isolation as barium salts. A knowledge of the percentage of barium present in these salts is often of importance in the study of their chemical nature. The determination of barium in small amounts has always, however, been attended with considerable difficulty. The well-known method of Pregl [1930] for sulphate is easily adapted to the determination of barium and gives excellent results, as also the newer Emich [1931] procedure for barium, using the filter-stick, which has proved so useful in microgravimetric analysis. Both these methods are thoroughly reliable, but require special apparatus, including a micro-balance, and a rather refined anid specialised technique.