A study of derivative spectrophotometry for the determination of carboxyhemoglobin in blood

An application of derivative spectrophotometry to the determination of carboxyhemoglobin (HbCO) in blood was examined. The 1st, 2nd, 3rd, and 4th derivative spectra were recorded in the Soret region for HbCO, reduced hemoglobin (Hb), and their mixed solution. The 4th derivative spectrum had the highest sensitivity to the change of HbCO-Hb ratio in the solution. A maximum point of the 4th derivative curve was employed for the HbCO determination. Blood samples with varied HbCO concentrations were analyzed using this technique and the results were compared with those obtained by conventional spectrophotometric and gas chromatographic procedures. The derivative method was in satisfactory agreement with both procedures.