The Microdetermination of Chlorides in Biological Materials

In the method the Volhard reaction and the open Carius digestion of Laudat (1917) are used.The microvolumetric measurements are made with the precision syringe of Krogh and Keys (1931) a&l the Rehberg burette (1926).Reagents and Apparatus-Ammonium thiocyanate, NH&N& approximately 0.1 N (0.76 gm. in 100 ml.).Silver nitrate, AgN03, approximately 0.2 N (34 gm. in 1 liter).Keep in a dark bottle.Ferric alum, Fez(SO&.(NH&Sob.24H,O.Dissolve 40 gm. in 100 ml. of hot water, allow to cool, and add 5 ml. of concentrated nitric acid.Ether, chloride-free.Hydrogen peroxide, 30 per cent (superoxol or perhydrol).Sodium or potassium chloride, standard solutions 0.1, 0.8, and 0.5 N.Prepare from recrystallized, dried salts.Syringe-pipettesl(Krogh and Keys, 1931), illustrated in Fig. l,A.These greatly improve the ease and accuracy of the procedure.One, for blood, red cells, plasma, etc., should be set at about