Model uv 2600 spectrophotometer

Transmission electron microscopy (TEM) and High-resolution TEM (HRTEM) images were obtained using an FEI TecnaiTF-20 field emission HRTEM operating at 200 kV. Samples were prepared by dropcasting of NP solution (both normal and acid treated) on 300-mesh amorphous carbon-coated copper grid and allowed to dry overnight at room temperature. Absorbance spectra were recorded to inspect the effect of acid treatment on spectral properties and concentrations of the NPs. To compare recyclability of the acid treated NPs to normal ones, we spectrophotometrically monitored bilirubin decomposition kinetics up to ten cycles. The experiment was started with equimolar concentration (10 µM) of bilirubin and catalyst for the first cycle and after every 15 min we added same dose of bilirubin into the reaction mixture. All absorption studies were performed using quartz cuvettes of either 0.4 cm (for serum samples) or 1 cm path length using a Shimadzu Model UV-2600 spectrophotometer.

Enzymatic activity of CHT was conducted with 0.5 µM of CHT at different formalin concentrations (1%, 2%, 4%). The substrate Ala-Ala-Phe-AMC (λ_max = 325 nm) was cleaved to produce 7-amido-4-methyl-coumarin (λ_max = 370 nm), the absorbance of which was monitored in Shimadzu Model UV-2600 spectrophotometer.