To begin FTIR characterization of curcuma longa extract, first clean the ATR crystal with two propanol. Then use the measure option on the instrument, and click on the basic tab. With a Pasture pipet, apply 0.3 milliliters of crude curcuma longa extract onto the ATR crystal.
Now, click on measure, followed by advanced, and set the file name. Then press the basic tab, and measure the IR transmittance of the dried extract. To perform UV visible measurement of the extract, first keep the spectrophotometer on for 15 to 30 minutes, then fill the reference cell with ethanol.
Next, click on the setup option and the carry tab to set the measurement parameters. Set the scan time to 0.1 seconds, data interval to one nanometer, and the scan rate of 600 nanometers per minute. Then set the wavelength range from 200 nanometers to 700 nanometers.
Prepare 25 milliliters dilutions of curcuma longa extract in increments of one to 100, with ethanol as the solvent. After transferring 3.5 milliliters of the diluted extract into a quartz cuvette, measure its absorbance. After the first measurement, clean the cuvette with ethanol.
Thoroughly rinse the cuvettes with the diluted extract, then fill it with the test solution to ensure the accuracy of absorption measurements. FTIR analysis of the extract showed significant peaks at various lengths corresponding to its functional groups. UV analysis showed a broad absorption spectrum, ranging from 350 to 500 nanometers.
The positive correlation between the absorbance and the concentration showed good linearity.
