Advances in a method for gas analysis in metabolic experiments. Improved calibration of a Noyons diaferometer
Reproduction nutrition development (Print)
The aim of this paper was to develop an improved calibration method for the gas analysis technique used by Lokhorst (1959, 1966). The method consisted of a parallel analysis of respiration air at 25 °C by a chemical absorption method on a Lloyd's gas analysis apparatus and by a physical method based on the thermal conductivity of respiratory gases, using a Noyons diaferometer (Kipp), the apparatus we wished to calibrate. Physical measurements were made at room temperatures of 25 !C, 28 °C and
... 25 !C, 28 °C and 31 O C. Constant calibration coefficients could not be found by simple and multiple regression equations expressing data obtained by chemical analysis of C0 2 surplus (L1 CO 2 p. 100) and 0 2 deficit (0 0 2 p. 100) as a function of the deflections on each of the two diaferometers used. Multiple regression equations expressing A C0 2 p. 100 and 0 0 2 p. 100, each as a function of both deflections (d) on the C0 2 and on the 0 2 -diaferometer, are shown in table 1c. These equations proved to fit best the corresponding chemical analysis and were used for calculation of A C0 2 p. 100 and A 0 2 p. 100 in the experimental conditions described. Simple regression equations between physical measurements at different room temperatures indicated the possibilities and the problems of transformation of data from one room temperature to another. Introduction.