630 PHYSIOLOGICAL CHEMISTRY 



Benedict's Sulphur Reagent. 



Crystallized copper nitrate, sulphur-free or of known sulphur 



content 200 grams. 



Sodium or potassium chlorate 50 grams. 



Distilled water to 1000 c.c. 



Benzidine Solutions for Volumetric Sulphur Determinations. 



Rosenheim and Drummond.Rub 4' grams of benzidine (Kahl- 

 baum) into a fine paste with about 10 c.c. of water and transfer to a 

 2-liter flask with the aid of about 500 c.c. of water. Add 500 c.c. of con- 

 centrated HC1 (sp. gr. 1.19) and make up to 2 liters with distilled 

 water. 150 c.c of this solution, which keeps indefinitely, are sufficient 

 to precipitate o.i gram H 2 SO4- 



Bertrand Sugar Reagents. 1 (a) Copper Sulphate Solution. Forty 

 grams of pure crystallized copper sulphate are dissolved in water to 

 make a liter. 



(>) Dissolve 200 grams of Rochelle salts and 150 grams of NaOH in 

 water to make 1000 c.c. 



(c) Acid Ferric Sulphate Solution. Dissolve 50 grams of ferric sul- 

 phate in about 200 c.c. of water and pour into this a mixture of 200 c.c. 

 of concentrated sulphuric acid diluted with about 400 c.c. of water. 

 Mix and make to 1000 c.c. 



(d) Potassium Permanganate Solution. Dissolve 5 grams of potas- 

 sium permanganate in water to make 1000 c.c. Standardization. 

 Dissolve 0.250 gram of ammonium oxalate in 50-100 c.c. of water, add 

 1-2 c.c. of concentrated sulphuric acid and titrate with the permangan- 

 ate to a rose color. Multiply the number of grams of oxalate used by 

 0.895 to get the equivalent in Cu of the number of cubic centimeters of 

 permanganate used. Calculate the Cu value of i c.c. 



Bial's Reagent. 2 



Orcinol 1.5 grams. 



Fuming HC1 500.00 grams. 



Ferric chloride (10 per cent) 20-30 drops. 



Biuret Reagent, Gies. 3 This reagent consists of 10 per cent KOH 

 solution to which 25 c.c. of 3 per cent CuSO 4 solution per liter has been 

 added. This imparts a slight though distinct blue color to the clear 

 liquid. 



Biuret Paper (Kantor and Gies). 3 Immerse filter paper in Gies' 

 Biuret Reagent (above) then dry and cut into strips. 



1 Determination of sugar, p. 545. 

 1 Test for pentose, p. 37. 

 3 Protein tests, p. 99. 



