Preparation, characterization and application of haemoglobin nanoparticles for detection of acrylamide in processed foods.

The nanoparticles of haemoglobin (HbNPs) were prepared by desolvation method and characterized by transmission electron microscopy (TEM),UV-vis spectroscopy, Fourier transformation infra red (FTIR) spectroscopy and X-ray diffraction (XRD) and atomic force microscopy (AFM). Protein profile of HbNPs was also studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). An amperometric acrylamide biosensor was constructed by immobilizing covalently HbNPs onto polycrystalline Au electrode. The Au electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectra (EIS) before and after immobilization of HbNPs. The biosensor showed optimum current response within 2s at 0.26V, pH 5.0 at room temperature (20°C). The biosensor measured the acrylamide concentration in processed foods. The working range of biosensor was 0.1nm-100mM with a limit of detection (LOD) as low as 0.1nM. The biosensor measured acrylamide concentration in various processed foods such as biscuits, bread, potato crisps, "kurkure", nuts and fried cereals. The analytical recovery of added acrylamide in aqueous extract of food at 5 and 10mM was 99% and 98% respectively. Within-and between-batch, co-efficient of variations were 3.85% and 4.67% respectively. The structural analogs of acrylamide such as acrylic acid and propionic acid had practically no interference on the biosensor.