ml. 0.500M Citric Acid 



22.36 

 21.30 

 20.28 

 19.40 

 18.56 

 17.70 

 16.80 

 15.82 

 14.74 

 13.56 

 12.30 

 10.90 



9.10 



7.06 



5.22 



3.66 



2.54 



1.70 



1.10 



UNIVERSAL BUFFER (TEORELL) 

 pH 2.0 - 12.0 

 Reference: Teorell, Tand and Stenhagen, Biochem. Zeitschr 



299 416-9 (1938) 



General : 



This buffer contains the buffer anions phosphate, borate, and citrate. 

 It covers the pH' s 2 - 12, and has a practically linear buffer capacity in 



the range pH 3 - 11. Between these values, 5 ml. of O.IN acid or base 



shifts the pH about 1 unit. The molarities of the various ions in the 

 final buffers are as follows: 



Phosphate - M/lOO Borate - M/lOO 



Citrate - M/150 Sodium - M/15 

 Standard Solutions: 



1) l.OOON NaOH...See section on standards. 



2) O.IOOON HCl...See section on standards. 



3) IN Phosphoric Acid (H3PO4) ... Dilute 17.5 ml. of 85% highest grade 

 H3PO4 to 500 ml. Standardize by titrating against 20 ml. aliquots of the 

 standard NaOH, using phenolphthalein indicator. The end-point is taken 

 as last trace of rose color, after the initial bright red has lightened 



-48- 



