An improved method for the automated determination of urine calcium.
The problems of accurately determining urine calcium are described. The basic technique described is little changed from that originally used by Clark and Collip but the pitfalls encountered when applying this to automated procedures are demonstrated and a means of overcoming them proposed.
EVALUATION OF PROCEDURES FOR URINARY CALCIUM.
In a comparative study of urinary calcium methods, many of the recently proposed procedures proved either impractical or invalid in our hands. A preliminary isolation of the calcium as the oxalate, followed by perchloric acid oxidation of the oxalate seemed to be the simplest procedure whereby urinary calcium could be put in a state suitable for chelometric titration. The isolated calcium could also be titrated with considerable precision and accuracy by a modified procedure with a derivative automatic titrator which is available commercially.

It was suggested from our observations that too little attention has been directed towards the problems imposed by the occurrence of calcium precipitates in urine. An untreated 24-hr. urine specimen is not suitable for direct analysis of calcium by chelometric titration, by colorimetric analysis, by emission flame photometry, or by atomic absorption flame photometry because these methods do not give a true measure of the calcium in the precipitate. Boiling for 5 min. with 1 part concentrated nitric acid to 25 parts urine proved a suitable means for completely dissolving the calcium precipitate.
IDENTIFICATION BY MEANS OF L-PHENYLALANINE INHIBITION OF INTESTINAL ALKALINE PHOSPHATASE COMPONENTS SEPARATED BY STARCH GEL ELECTROPHORESIS OF SERUM.
After electrophoresis of serum on starch gel, the alkaline phosphatase-rich zones which undergo inhibition by l-phenylalanine, a specific inhibitor for the intestinal enzyme, have been clearly defined and quantitatively measured. 
 
Serum from normal subjects, with a major peak of alkaline phosphatase activity in the fast α2 region, shows some intestinal alkaline phosphatase on the trailing edge of the peak. Occasionally a second intestinal peak is observed in the haptoglobin region, where alkaline phosphatase activity of intestinal tissue extracts is found7. This is also the location of an intense activity present in the serum from some cirrhotic patients. Another cirrhotic with a normal percentage of intestinal component but with highly elevated alkaline phosphatase total, exhibited no haptoglobin peak. These subjects are examples of two categories of cirrhotic patients with elevated serum alkaline phosphatase6, one in which the intestinal component is predominant and one in which it is not.