[Studies of pure human pancreatic juice].

The test-combination from Fa. Boehringer Mannheim GmbH for measuring citric acid present in foodstuffs is also suitable for use in human pancreatic juice. Accuracy, within-run and between-day imprecision are satisfactory. The detection limit of the method is at least 10 mumol citrate/l pancreatic juice. The limit can be reduced when exact additions of citrate are given to the pancreatic juice and then evaluated using regression analysis. The presence of Ca-ions and possibly also trypsin in the material to be tested does not interfere with the reaction. It is, however, necessary to remove proteins from the sample. Deproteinization can be performed either by ultrafiltration or with perchloric acid.