Model 8400 s

This analysis was conducted using an FTIR spectrophotometer (Shimadzu Model 8400S, Shimadzu, Noisiel, Marne-la-Vallée, France). A homogeneous mixture was prepared by dissolving one milliliter of the biosurfactant sample in potassium bromide pellets to create the samples (Merck, Rahway, NJ, USA). An integrated plotter was used to generate IR absorption spectra. The IR spectra were acquired with a resolution of 4 cm⁻¹, covering a wavelength range of 450–4500 cm⁻¹. The spectral measurements represented the average of 50 scans across the instrument’s complete operating range.

The chemical structure of CHQ derivative was examined at 400 MHz using nuclear magnetic resonance (1H NMR, Bruker DRX-400 spectrometer, USA) and Fourier transform infrared spectroscopy (FTIR, Model 8400 S, Shimadzu, Kyoto, Japan). The FTIR spectra were recorded at 4000–500 cm⁻¹ using 5 mg of dried sample and KBr discs. The morphological properties were investigated a Scanning electron microscope (SEM; Model JSM 6360 LA, Joel, Japan). Prior to SEM analysis, the tested dry sample was spread out on a double-sided conducting adhesive tape, fixed on a metallic stub, and then coated with a thin layer of gold.

Samples of the polymers were prepared in KBr disks in a hydrostatic press at 6–8-ton pressure. FTIR spectra of these prepared samples were recorded at scanning range of 350 to 5000 cm⁻¹ using a spectrophotometer (model 8400S, Shimadzu Corporation, Koyto, Japan).

The pH and Electrical Conductivity of the samples were determined at a solid to water suspension ratio of 1:2.5 using digital pH meter and conductivity meter, respectively. The heavy metal content (Cd, Cr, Ni and Pb) of the acid digested samples were determined in Atomic absorption spectrophotometer (Perkin Elmer AA analyst 400). The proximate characterization of PBM-ETPS and PBM-ETPSH were carried out by standard ASTM procedures (ASTM-E871-82, ASTM-D3175-07 and ASTM-D3174-04). The ultimate composition (C, H, N, S and O) was determined by Elementar vario EL III. The BET Surface area and pore volume were determined by smartsorb 92/93 surface area analyzer. The surface morphologies and texture characteristics of the samples were interpreted by scanning electron microscope M/s. FEI - Quanta 250, Czech Republic taken at a high voltage of 8 kV with 10,000x magnification and transmission electron microscope M/s. FEI - Quanta 250, Czech Republic operating at an accelerating voltage of 120 kV¹⁰ . The functional groups were determined using FTIR (Model 8400 S of Shimadzu, Japan) over the wavenumber range of 400–4000 cm^{−1 11 (link)}. The particle size and zeta potential were measured using the particle size analyzer, Horiba Scientific Nanopartica SZ-100, Japan^{12 (link)}.

A sample each of metronidazole, chitosan, microcrystalline cellulose, and physical mixture of the three materials was prepared in a potassium bromide disk in a hydrostatic press at 6 to 8 tons pressure. The FTIR spectrum of each sample was recorded at scanning range of 350 to 4000 cm⁻¹ using a spectrophotometer (Model 8400S, Shimadzu Corporation, Kyoto-Japan).

The average sizes of the prepared Alg, single, and dual PECs microcapsules were measured in a triplicate using a micrometer screw gauge. Investigation of the functional groups of the native CMCs derivative, native AmCs derivative, and the developed microcapsules was achieved using Fourier transform infrared spectroscopy (FT-IR, Model 8400 S, Shimadzu, Japan). Samples (5–10 mg) were mixed thoroughly with KBr (spectral purity), and the test temperature was set at 25 °C. The absorbance of samples was scanned in the wavenumber range of 500–4000 cm⁻¹. Moreover, the thermal properties were inspected by the thermogravimetric analyzer (TGA, Model 50/50H, Shimadzu, Japan). TGA test was performed at a temperature range of 10–800 °C under nitrogen atmosphere with a flow rate of 40 mL/min, and the heating rate was 20 °C/min. Besides, a scanning electron microscope (SEM, Model JSM 6360 LA, Joel, Peabody, MA, USA) was employed to investigate the topographical properties of microcapsules under voltage potential of 15 kV. Prior to SEM examination, the tested samples were placed on aluminum stubs and coated with a thin layer of gold using a sputter coating system.