Poly(methylene blue) modi®ed electrode sensor for haemoglobin

Poly(methylene blue) modi®ed electrodes have been prepared by potential cycling from aqueous electrolyte solution containing methylene blue on glassy carbon substrates. They have been used successfully for the determination of haemoglobin via its electrooxidation at ®xed potential using the batch injection analysis technique in which whole blood samples diluted with phosphate or acetate buffer are injected directly over the modi®ed electrode immersed in inert electrolyte. Electrode response is fast, stable, and reproducible. For blood from healthy donors, a good linear correlation was found between the results from the electrochemical injection method and the conventional clinical spectrophotometric measurement after cyanidation. The blood from potentially ill donors showed deviations from the linear correlation suggesting that this may be a good method for detecting haematological problems. # 1999 Elsevier Science B.V. All rights reserved.