2013-10-11 by seoer8Water solubles take this product 2.0g, add water 100ml, a water bath heated to reflux for 2 hours , filtered, the residue washed with a small amount of water , the combined filtrate and washings , set by the constant weight of 105 ℃ evaporating dish, evaporated, at 105 ℃ drying to constant weight , no residue left over 20mg (1.0%). Acid insoluble take this product 2.0g, add hydrochloric acid 25ml, heated in a water bath to dissolve , add water 100ml, used by 105 ℃ constant weight on the 4th vertical melt crucible filtration residue with hydrochloric acid (1 → 100) to wash lotion colorless , then washed with water to wash no significant chloride reaction at 105 ℃ drying to constant weight , no residue left over 20mg (1.0%). Loss on ignition To about 1.0g, accurately weighed, at 700-800 ℃ ignition to constant weight , less weight loss should not exceed 12.0% . Barium salt to take this product 0.2g, add hydrochloric acid 5ml, heated to dissolve , dropping a drop of hydrogen peroxide solution , add 10 % sodium yellow iron oxide solution 20ml, filtration residue was washed with water 10ml , the combined filtrate and washings , sulfuric acid solution (2 → 10) 10ml, not significant turbidity . Lead salts take this product 0.5g hydrochloric acid 10ml, heat to dissolve, add nitric acid 3ml, boil 1 minute , let cool, shaking with anhydrous ether extracted four times (30m, 20ml, 20ml and 20ml), discard the ether layer , heated to remove residual acid in ether, ammonia solution is alkaline , add potassium cyanide solution 1ml, add water to 50ml, add a few drops of sodium sulfide solution , shake, such as color, with a standard lead solution 1.5ml were made using the same method was compared, no more ( 0.003% ) . Arsenic take this product 0.2g, add hydrochloric acid 7ml, heated to dissolve , add water 21ml, dropping the yellow faded acidic stannous chloride solution , according to inspection ( Appendix Ⅷ J first law ) , shall meet the requirements ( 0.001% ) .