QUANTITATIVE DETERMINATION OF CREATININE

摘要

PURPOSE:To determine quantitatively, quickly and exactly creatinine without receiving the influence of coexisting materials by adding creatinine dimynase to a sample and detecting the change rate of electrical conductivity, etc. by using electrodes for measuring electrical conductivity coated with porous films thereby determining the NH3 formed from the creatinine. CONSTITUTION:A buffer soln. of a measuring cell 3 provided with electrodes 1, 1 for measuring electrical conductivity each formed by bringing a porous film 10 made of polycarbonate or the like having 0.001-0.1mu pore size into tight contact with a platinum electrode 11 and fixing the same by means of an O-ring 9 is put into cell chambers 4. A creatinine dimynase soln. is then put therein through an injecting port 6 and is stirred and mixed uniformly by a diaphragm 5 until the electrical conductivity attains a specified value and thereafter the sample dissolved by a phosphoric acid buffer soln. is injected into the cells through the port 6. The change rate of the conductivity by NH3 generated by reaction in 1-5min after the injection is measured. The exact creatinine concn. is known by using the calibration curve for the change rate of the conductivity and the creatinine concn. obtd. preliminarily with a known standard sample. The sample and quick measurement of the creatinine is thus made possible even with the sample such as blood or the like contg. coexisting materials such as blood cells and protein, etc. without being influenced by such materials.