How to analyze calcium lignosulfonate

A. 15 lignin content (β- naphthylamine method )
A. 15.1 Equipment
a. Analytical balance ( weighing 200g, a sense of volume 0.1mg);
b. Pipette (10ml);
c. Water bath ;
d. G4 filter bowl .
A. 15.2 Reagents
a. Hydrochloric acid : 0.3N
b. β- naphthylamine hydrochloride solution (C10H7NH2 light HCl): 7.5gβ- naphthylamine were dissolved in hydrochloric acid solution 250ml0.3N , if dissolved , can be slightly heated and filtered to be dissolved after use .
A. 15.3 Test procedure take 1.0g calcium dissolved in 100ml volumetric flask of wood with 0.3N hydrochloric acid to adjust the pH to 3 ( Congo red paper blue ) , plus β- naphthylamine hydrochloride solution 10ml, stir uniform, placed 100 ℃ boiling water bath for an hour, fine yellow precipitate formed gradually , slowly turned orange and brown , and finally the formation of gum. G4 is then filtered using a known weight of the filter cup at 100 ± 2 ℃ oven dried to constant weight , weighed to cool to room temperature in a desiccator .
A. 15.4 The results of the processing of calcium lignosulfonate content is calculated as follows :
Calcium lignosulfonate (%) = a × 0.842 × 1.22 × 100/1.0 = a × 102.72 (A.15)
Where a – precipitation Weight (g);
1.22 – correction factor ; due to precipitation in the β- naphthylamine hydrochloride solution , about 18% lignin sulfonate was not precipitated , still in solution , so to several revisions ; 0 . 842 – β- naphthylamine lignin sulfonate converted into calcium lignosulfonate coefficients.