Determination of Oxygen,Carbon Dioxide,and Nitrous Oxide in Blood by Gas Chromatography

Abstract

A gas chromatograph (Beckman) was modified for determination of blood O₂, CO₂ and N₂O content with i. a. a new extraction tube. Different characteristics in volume of extraction tube, carrier gas (Helium) flow, volumes of reagents and times for reaction between reagents and blood were investigated. The method was standardized for a blood sample volume of 0.5 ml for O₂ and CO₂ analysis and 1.0 ml for N₂O. The time for a complete analysis of O₂ and CO₂ was 12 min and for N₂O 7 min. Double determinations with the Van Slyke and Neill method and gas chromatography did not differ significantly for either O₂ or CO₂ within the physioldfeical range. N₂O analyses were also consistent with both methods for contents occurring during, e. g., measurement of cerebral blood flow (up to 6 ml/100 ml). The reproducibility determined from duplicate analyses was similar with both methods, with the exception of the N₂O analyses, where the gas chromatograph (M=3.22 ml/100 ml, SD of the mean = 0.009) appeared to yield more consistent values than the Van Slyke and Neill method (M=3.29 ml/100 ml, SD of the mean = 0.020).