The content of carboxyl groups in organic matter can be determined by acid-base titration. The following are general carboxyl content determination methods:
Sample preparation:
Dissolve the organic sample to be tested in an appropriate solvent to achieve the appropriate concentration. Make sure there are no other interfering substances in the sample.
Acid-base titration: Transfer the dissolved sample solution to a titration bottle and add an appropriate amount of acid-base indicator, such as phenolphthalein indicator or bromophenol blue indicator.
Titration process:
Use a standard alkali solution (such as sodium hydroxide solution) to titrate the carboxyl groups in the sample. During titration, the carboxyl groups neutralize with the base to produce the corresponding salt and water.
End point indication:
During the titration process, the color of the solution changes as the acid-base titration progresses. When the solution changes from acidic to basic, the color change will indicate the end point of the titration.
Calculation of carboxyl group content:
According to the concentration of the standard acid-base solution used in the titration process and the volume of the acid-base solution consumed in the titration process, the content of carboxyl groups in the sample can be calculated. Calculate and get the result according to the chemical equation and calculation formula of the acid-base titration reaction.
It should be noted that different organic substances may require different titration conditions and indicators. Therefore, when determining the carboxyl group content, appropriate experimental methods and reagents should be selected according to the specific organic substance type and experimental requirements, and corresponding operating procedures and standards should be followed.
