2.7. Characterization of PHAs

The dried sample of PHAs extracted by sodium hypochlorite method was subjected to Fourier transform infrared (FTIR) spectroscopy study. The analysis was performed by using KBr Pellet method [23], and the absorption was recorded in the range of 4000–450 cm⁻¹ (Perkin-Elmer Spectrum-II spectrometer, MA, USA).

In order to perform thin layer chromatography (TLC), the extracted PHA was dissolved in chloroform, and chromatography was performed on a TLC plate coated with silica (230–400 mesh size) [24]. Methanol and chloroform were used as solvent system in various ratios. After completion of the TLC run, the plates were air dried and visualized under iodine chamber and UV chamber; afterwards, the R_f values were calculated.

¹H-NMR spectrum of the sample (i.e., PHAs) was obtained by using a Bruker AvIII HD-300 spectrophotometer. The spectrum was recorded at 300 MHz against TMS (tetramethylsilane) as internal reference standard. Approximately 5 mg of PHAs was dissolved in 2 mL CDCl₃ (deuterated chloroform) for sample preparation.

The crystalline nature of the produced PHAs was determined by using X-ray diffractogram with K-β filter (40 mA, 40 KV) source of radiation done by powder method. The sample of PHAs was freeze-dried in a capillary tube. The scan speed was kept as 3.000 degree/min and the scan range was in between 10,000–80,000 degrees.