The ferric reducing anti-oxidant power (FRAP) assay involved the following steps: a) preparation of samples, b) reactions and c) finally measuring absorbance of sample and standard at 700 nm using spectrophotometer. The samples were methanolic extract, different fractions (n-hexane, chloroform) and standard ascorbic acid. The solutions prepared were buffer solution (pH 6.6), 1% potassium ferricyanide solution, 10% trichloroacetic acid and 0.1% ferric chloride. Video ClipFerric reducing anti-oxidant power assay:21 min 18 sec

Environmental pollution caused by heavy metals is a serious threat. In the present work, removal of chromium was carried out using chitosan–magnetite nanocomposite strip. Magnetite nanoparticles (Fe₃O₄) were synthesized using chemical co-precipitation method at 80 °C. The nanoparticles were characterized using UV–visible spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction spectrometer, atomic force microscope, dynamic light scattering and vibrating sample magnetometer, which confirm the size, shape, crystalline nature and magnetic behaviour of nanoparticles. Atomic force microscope revealed that the particle size was 15–30 nm and spherical in shape. The magnetite nanoparticles were mixed with chitosan solution to form hybrid nanocomposite. Chitosan strip was casted with and without nanoparticle. The affinity of hybrid nanocomposite for chromium was studied using K₂Cr₂O₇ (potassium dichromate) solution as the heavy metal solution containing Cr(VI) ions. Adsorption tests were carried out using chitosan strip and hybrid nanocomposite strip at different time intervals. Amount of chromium adsorbed by chitosan strip and chitosan–magnetite nanocomposite strip from aqueous solution was evaluated using UV–visible spectroscopy. The results confirm that the heavy metal removal efficiency of chitosan–magnetite nanocomposite strip is 92.33 %, which is higher when compared to chitosan strip, which is 29.39 %.