REAGENTS AND SOLUTIONS 633 



Folin-McEllroy Reagent 1 . Dissolve loog. of sodium pyrophosphate, 

 30 g. of disodium phosphate and 50 g. of dry sodium carbonate in approx- 

 imately i liter of water by the aid of a little heat. Dissolve separately 

 13 g. of copper sulphate in about 200 c.c. of water. Pour the copper 

 sulphate solution into the phosphate-carbonate solution and shake. 



Folin-McEllroy-Peck Reagents for Sugar in Urine. 2 (a) Acidified 

 Copper Sulphate Solution. Dissolve 59 gm. of CuSO 4 5H 2 O in water 

 together with 2 c.c. of concentrated sulphuric acid and make up to i 

 liter. Five c.c. of this solution correspond to 25 mg. of glucose or 

 fructose, 45 mg. of anhydrous maltose, or 40.4 mg. of anhydrous 

 lactose. 



(b) Phosphate-carbonate-thiocyanate Mixture. Powder in a large 

 mortar 200 gm. of crystallized disodium phosphate (HNa 2 PO 4 -i2H 2 O) 

 and sprinkle over it about 50 gm. of sodium thiocyanate (or 60 gm. 

 of potassium thiocyanate). Mix for 10 minutes with pestle and spoon, 

 giving a uniform semi-liquid paste. Add "about 120 gm. of monohy- 

 drated sodium carbonate (or 100 to no gm. of anhydrous carbonate) 

 and mix with pestle and spoon until a rather fluffy, granular powder is 

 obtained. To test the completeness of the mixing and 5 gm. of the 

 powder to 5 c.c. of the copper solution; if any black specks are formed, 

 even temporarily, the mixing is incomplete. A certain amount of 

 green color is, however, practically unavoidable when this test is 

 applied. If no black coloration is obtained allow the mixture to stand 

 in the mortar for a few hours or over night (covered with paper) mix 

 once more and transfer to bottles. In stoppered bottles the mixture 

 keeps indefinitely. 



Folin-Shaffer Reagent. 3 This reagent consists of 500 grams of am- 

 monium sulphate, 5 grams of uranium acetate, and 60 c.c. of 10 per 

 cent acetic acid in 650 c.c. of distilled water. 



Folin's Sugar Reagent. The reagent is made up in two solutions : 

 A. Five grams of crystallized copper sulphate are dissolved in 100 c.c. 

 of hot water and to the cooled solution are added 60-70 c.c. of pure 

 glycerol. 



B. One hundred and twenty-five grams of anhydrous potassium 

 carbonate are dissolved in 400 c.c. of water. 



One part of the glycerol-copper solution (A) is mixed with two parts 

 of potassium carbonate solution (B). Only small portions should 

 be mixed at a time as the reagent (after mixing) does not keep but under- 

 goes gradual reduction. 



1 Folin-McEllroy Test, p. 435. 



2 Folin-McEllroy-Peck Method, p. 540. 



3 Folin-Shaffer method, p. 532. 



