[FTIR-microspectrophotometry for high resolution and highly sensitive detection of the carboxyhemoglobin complex]

Our recently developed method for rapid quantitative evaluation of carboxyhemoglobin in liquid as well as in dried blood samples has been considerably improved by the incorporation of an infrared microscope. Besides the characteristic bands at V = 1953 (cm-1) in liquid and V = 1968 (cm-1) in dry blood we found, upon addition of D2O, a dislocation of the bands at V = 1949 (cm-1). This reversible dislocation still permits a reliable identification of the COHb complex at the extremes of the capacity range of the measuring unit. Thus identification of the COHb complex was successful even in isolated erythrocytes. By means of this improved technique reliable quantitative evaluation may be carried out in a concentration range of between 2% and 0.05% whereas semiquantitative evaluation was possible at concentration down to 0.01%, allowing for instance the evaluation of the effects of a single inhalation of cigarette smoke. The positive identification of endogenous COHb fractions as well as of exogenous agents (smoking, environmental factors) which this method permits is prerequisite for a dependable interpretation of forensic-toxicologically relevant COHb findings.