Carbon Monoxide Analysis: A Comparison of Two Co-Oximeters and Headspace Gas Chromatography

Abstract

Three methods (IL-182 Co-Oximeter, IL-282 Co-Oximeter, and headspace gas chromatography) for the analysis of carbon monoxide in postmortem blood were studied and compared using a prepared reference standard, Quantra control materials, and 62 postmortem blood specimens. The methods compared favorably with one another. The linear regression equations for the 62 postmortem blood samples (range = 1.0 to 86% saturation) were: IL-282 vs. IL-182, y = 1.11x - 3.10, r = 0.981; IL-182 vs. GC, y = 0.88x + 2.97, r = 0.973; IL-282 vs. GC, y = 1.00x - 1.24, r = 0.986.

Concentration of Carbon Monoxide (CO) in Postmortem Human Tissues: Effect of Environmental CO Exposure*

“…The degree of exposure to CO is most often assessed through measurements of COHb, most commonly with clinical spectrophotometric methods (10,13). Although since the 1960s, the use of the gas chromatographic (GC) method has become more widespread in forensic toxicology laboratories (14)(15)(16)(17). However, the convenient, automated methods are limited to analysis of fairly intact blood even though some pretreatments, such as dithionite reduction, homogenization, and detergent treatment have been used to improve sample quality (10,15).…”

“…Although since the 1960s, the use of the gas chromatographic (GC) method has become more widespread in forensic toxicology laboratories (14)(15)(16)(17). However, the convenient, automated methods are limited to analysis of fairly intact blood even though some pretreatments, such as dithionite reduction, homogenization, and detergent treatment have been used to improve sample quality (10,15). Furthermore, analysis of aged, clotted, partially degraded, and/or heat-exposed postmortem blood is usually beyond the capability of these methods.…”

Carbon Monoxide

“…Both gas chromatography and spectrophotometry are considered appropriate, although the former is favored (Coburn et al, 1964;Collison et al, 1968;Vreman et al, 1984Vreman et al, , 1998Kane, 1985;Constantino et al, 1986). However, blood CO is still measured by determining COHb levels, which are normally undetectable but might be involved in the transfer of CO between cells.…”

Accuracy profile validation of a new method for carbon monoxide measurement in the human blood using headspace-gas chromatography–mass spectrometry (HS-GC–MS)

“…Numerous methods have been described to study the effect of the added reagent to whole blood on the liberation of CO. Potassium ferricyanide was the most commonly used substance as the liberating agent [4,5,[10][11][12][13][14][15] and resulted in better CO release than potassium ferrocyanide, especially when mixing was applied [16,17]. Acids, such as sulfuric acid [9,13,[18][19][20][21], lactic acid [13], citric acid [13,16], and phosphoric acid [16] have also been studied, and have provided good results.…”

“…This detector has been improved upon to produce the micro TCD, which is a more convenient [18,19,33] method. An alternative to the TCD is Flame Ionization Detector (FID) that is coupled to a nickel catalyst placed before the FID [3,10,11,15]. The use of the FID provides the specificity and sensitivity required at low CO levels through the conversion of CO to methane by a nickel-hydrogen reduction [17,34].…”