A potentiometric sensor for the trace level determination of hemoglobin in real samples using multiwalled carbon nanotube based molecular imprinted polymer

A novel potentiometric sensor was developed with high selectivity and sensitivity for the detection of hemoglobin using surface modified multiwalled carbon nanotube (MWCNT). MWCNT is first oxidized using concentrated nitric acid, and then grafted with epichlorohydrin (ECH). The epoxide ring present on the surface of MWCNT reacts with allyl alcohol in presence of sodium to form vinylated MWCNT (MWCNT-CH==CH2). MWCNT based imprinted polymer (MWCNT-MIP) was prepared by means of itaconic acid (IA) as the monomer, ethelene glycol dimethacrylate (EGDMA) as the cross linker, alpha, alpha'-azobisisobutyronitrile (AIBN) as the initiator and hemoglobin (Hb), a metalloprotein as the template molecule. MA, XRD, Raman and SEM analyses were carried out for the characterization of MWCNT-MIP. The optimizations of analytical parameters were also done. The prepared MWCNT-MIP sensor exhibited not only high selectivity toward Hb in comparison to other interferents, but also a wide linear range over Hb concentration from 1.0 to 10.0 mu g/mL with a detection limit of 1.0 mu g/mL (3 sigma) and the slope obtained for MWCNT-MIP was 42.639 mv/decades. The people with hematuria the concentration of hemo in the urine is of about 1.0 mg/ml. In this report, hemo can be sensed in urine with sensitivity of 1.0 mu g/ml and the sensitivity is sufficient in physiological fluids like bile juice. The stability of sensor was checked and it is found to be 6 months and it can be reused several times without losing its sensitivity. The developed sensor was successfully applied for human bile juice and urine samples.