Direct Electrochemical Determination of Hemoglobin in Blood Using Iodine-Coated Platinum Polycrystalline Electrode

A direct method for hemoglobin determination in blood was developed using iodine-coated platinum electrode. The electrochemical behavior of iron ions in hemoglobin within human red blood cells was investigated by cyclic voltammetry at iodine-coated platinum electrode. A well-defined peak assigned to oxidation of hemoglobin was observed at about 0.4 V. A more prominent peak for the oxidation of hemoglobin was observed at pH 5.5 in 0.9% NaCl solution compared to phosphate puffer solution of pH 3.5. Using hydroxylamine in the dry form with the hemoglobin in red blood cells enhanced the peak current for hemoglobin oxidation by 14 folds. A linear relationship between the hemoglobin oxidation peak current and the concentration of hemoglobin was illustrated within the concentration range from 1.53 g dl-1 to 9.2 g dl-1 with a correlation coefficient (R2 = 0.9949). The estimated detection limit based on S/N = 3 ratio was 0.004 g dl-1. The developed method was directly applied to determine hemoglobin without pretreatment of the blood sample. The developed method passed the tests for its liability towards interferences. The developed method was validated against the regular clinical analysis for hemoglobin. Analysis of real samples by the two methods indicated the absence of systematic errors as indicated by the confidence limits at 95% confidence level. Moreover, application of the null hypothesis to the results of two methods indicated the validity of the null hypothesis; no significant difference was observed between the two methods at p = 0.05.