A carboxyl group is a chemical functional group that is often used as a raw material for acidic substances and drugs. The method of determining carboxyl content varies with different compounds, the following are two commonly used methods:
Acid-base titration:
Dissolve the sample to be tested in water, add phenolphthalein indicator and NaOH solution of known concentration, and titrate with HCl solution until the color of the solution changes from pink to orange. According to the titrated NaOH solution volume and known sample volume, calculate the carboxyl content in the sample.
UV absorption spectrometry:
Dissolve the analyte in an appropriate solvent, measure its absorbance at 240 nm with an ultraviolet spectrometer, and then calculate the carboxyl content in it according to the Lambert-Beer law. This method is suitable for the determination of carboxyl compounds such as benzenecarboxylic acid and phosphoric acid.
Beichao reminds you: Different samples and compounds may require different carboxyl content determination methods, and different methods may also have differences in operation process and determination results. Therefore, when selecting a method for the determination of carboxyl group content, it is necessary to select an appropriate method according to the characteristics of the substance to be tested and the required accuracy.
