A Method for Determination of Low Carbon Monoxide Concentration in Blood

Abstract

Abstract A method is described for the measurement of the CO content of blood, particularly at low concentrations. The error of a single determination was 1–3 per cent of the total amount of CO (range 0.7–70 μl) present in the analyzed sample. At an ordinary CO content of about 0.1 ml CO/100 ml blood the error was about ± 0.002 ml CO/100 ml blood (S.D.). Different procedures for the release of CO from the blood were compared. With K 3 Fe(CN) 6 and H 2 SO 4 equal and slightly smaller amounts of CO were obtained than with KH(JO 3 ) 2 , if blood with a low CO content was analyzed. Evidently KH(JO 3 ) 2 , although less than some other chemical agents (K 2 Cr 2 O 7 and NaOH), causes extra CO formation from the blood. In spite of the error due to this extra CO formation there were advantages to use KH(JO 3 ) 2 for analysis in higher ranges of CO concentrations, when this small error became insignificant. If extraction of CO from the blood with reagents such as K 3 Fe(CN) 6 , H 2 SO 4 or KH(JO 3 ) 2 took place at a high O 2 partial pressure slightly larger amounts of CO were obtained than with extraction in“vacuum” or in an atmosphere of N 2 . The results indicate that small amounts of CO may be formed during procedures used for the release of CO from blood, probably due to oxidative break down of hemoglobin.