Notes on the applicability of the BENEDICT-THEIS method for the determination of inorganic phosphorus in equine blood by FISHER's electrophotometer

Abstract

With the purpose of both traces the behaviour and to get acquainted with the particular technic of the BENEDICT-THEIS method in the FISHER’s electro-photometer, method preconized for the determination of inorganic phosphates in the blood, the AA., employing equine serum, made a series of determinations repeated in the same serum. After this they proceeded with the recovery test, adding different amounts of the phosphate solution to equal volume of the same serum, following the criterion generally adopted in such works. From the determinations obtained under the conditions in which they were performed, the AA. concluded that there is necessity of taking the readings soon after the color development, observing closely the procedure indicated to find the calibration factor. It was stated that the method answers satisfactory against the coefficient of variability, but, negatively to the recovery test, because according to T-test estimation, the results differ from the theoric ones with significance. They raise the supposition that the recovery fails due to the cautions demanded relatively to the time of color development and posterior cooling or inconsequence of one or various factors concerning the agreement of the method, in LAMBERT-BEER’s law.