| 摘要 |
1,151,608. Estimation of vitamin B 12 . PHARMACIA AB. 19 Oct., 1967 [21 Oct., 1966], No. 47604/67. Heading B1X. [Also in Division C3] Vitamin B 12 in an aqueous sample is estimated by contacting particles of a water insoluble epichlorhydrin crosslinked dextran derivative which has covalently bound to it the substance "intrinsic factor" (a muco protein from the ventriculus mucous membrane, and which is capable of binding Vitamin B 12 ; see Division C3), with the sample and with a predetermined amount of vitamin B 12 labelled with a radioisotope, and subsequently separating the particles from the sample liquid and measuring the radioactivity o,f the particles and/or of the liquid. Suitably the radioisotope is <SP>58</SP>Co. In the example a 0.05M tris-buffer at pH 7.4 containing NaCl, bovine serum albumin, and sodium azide is used as aqueous medium. The dextran reagent may be supplied in ampoules together with ampoules containing the labelled vitamin B 12 , to make a test pack.
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