Ferrous lactate analysis

Weigh accurately about 2g, heated slowly carbonized nitrate plus 2ml, attention not to the case of splashing, evaporated to dryness at 550 ~ 600 ℃ ignition to full ash (about 3h). Hydrochloric acid 10ml, boil until almost insoluble white, add water to 30ml, filtered, washed with water insoluble, Ethyl lactate and combined filtrate, add water volume to 100ml, 25ml to absorb iodine flask, add potassium iodide 4g Gasser, in dark for 15min, add water 100ml, with 0.1mol / L sodium thiosulfate droplets, drops to yellow, add 1% starch solution 1m1, continue titration until the end (yellow just disappears). While doing a blank test. Total iron content (%) = c (V2-V1) × 10 × 0.005585 / (W × 25/100) × 100
Where V1 - blank titration consumed 0.1mol / L potassium lactate m1 number;
V2 - the consumption of titration of the sample 0.1mol / L sodium thiosulfate number of ml;
c - the concentration of sodium thiosulphate solution, mol / L;
W - sample weight, g;
0.005585 - 0.1mol / L sodium thiosulfate 1ml equivalent weight of iron, g.
Ferrous Weigh 0.5g sample in Erlenmeyer flask, add 100ml of water and phosphoric acid 5ml, shake, coupled with concentrated sulfuric acid 5ml, shake, add 2 to 3 drops of diphenylamine solution (TS-89), with 0.1mol / L potassium permanganate standard droplet to remain pink 30s does not fade so far.