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THE FLUORIMETRIC ESTIMATION OF CORTISOL IN HUMAN PLASMA
Author(s) -
Purves HD,
Sirett Nancy E
Publication year - 1969
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1969.153
Subject(s) - reagent , methylene , chromatography , chemistry , chloride , pipette , methylene blue , ethanol , centrifugation , biochemistry , organic chemistry , photocatalysis , catalysis
Summary A method for the fluorimetric estimation of cortisol in human plasma is described. Technical modifications to existing methods include extraction of cortisol from plasma by vigorous agitation with methylene chloride followed by centrifugation, automatic pipetting of methylene chloride extracts and the use of reaction tubes with fused‐on cuvettes for the reaction with ethanol‐sulphuric acid reagent. These modifications make the method more convenient and the results more reproducible in relatively unskilled hands. The effects of reagent composition, temperature of reaction and reaction time on the specificity of fluorescence measurements have been explored. For measurements made at 10 min. after mixing the optimum ratio of sulphuric acid to rectified spirits in the reagent was 2:1 at 24.5° and 2.3:1 at 17.5°. The mean value of plasma cortisol measured in 23 ambulant adults at 9.30 a.m. was 18.1 μg./100 ml.The standard deviation of repeated measurements on different days of one normal plasma was ± 1.4 μg./100 ml.