Accession Number : AD0787314

Title :   Influence of Temperature on the Delta pH Method of Measuring Blood Cholinesterase.

Descriptive Note : Technical rept. Sep 73-Feb 74,

Corporate Author : EDGEWOOD ARSENAL ABERDEEN PROVING GROUND MD

Personal Author(s) : Ellin,Robert I. ; Vicario,Pasquale P.

Report Date : SEP 1974

Pagination or Media Count : 11

Abstract : Efforts to evaluate the precision of the Michel delta pH method of measuring cholinesterase activity, performed in a breaker immersed in a 25C water bath, resulted in unexpected variability in results of day-to-day replicate analyses. Most disturbing was the considerable variation between each 4-hour period of an 8-hour day (a.m. and p.m. measurements). Precision of quadruplicate sets, expressed as coefficient of variation, ranged from plus or minus 0.5% to 8.0%. By rigidly controlling temperature with a water-jacketed reaction vessel, the variation was reduced to plus or minus 1.7%. A study of the effect of temperature on the method showed that a 1-degree change in temperature resulted in a 5.5% change in plasma activity and a 3.0% change in red cell activity. A graphing of the influence of temperature on reaction rate produced a linear relationship. Identical thermodynamic data were obtained with plasma and red cell samples which were inhibited 50% with an with an irreversible anticholinesterase agent. (Author)

Descriptors :   *Cholinesterase, *Blood chemistry, Quality control, Enzymes, pH factor, Chemical properties, Tables(Data), Temperature, Quantitative analysis, Chemical analysis, Test methods

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE