1 Preface

Glycine, also known as aminoacetic acid, has the chemical formula C2H5NO2. It is a white solid at normal temperature and pressure. It is the simplest amino acid in the amino acid series and is not essential for the human body. In medicine, it is a drug for treating myasthenia gravis and progressive muscle atrophy. When used in combination with aspirin, it can reduce irritation to the stomach. It can also treat hyperproline-emia in children. This paper refers to the pharmacopoeia and uses the JH-T7 fully automatic titrator to determine its content. This process is simple to operate, minimizes the errors caused by manual titration as much as possible, and the repeatability of the experimental results is good.

2. Instruments and equipment

2.1 Instruments

JH-T7 fully automatic potentiometric titrator, PH composite electrode.

2.2 Reagents

Perchloric acid titrant (0.1 mol/L), anhydrous acetic acid, formic acid.

3 Experimental Methods

3.1 Experimental Procedures

Sample testing: First, record the temperature during titration and calibrate the concentration of perchloric acid solution. Accurately weigh 70mg of the sample to be tested and place it in a dry titration cup. Use a pipette to accurately draw 1.5mL of formic acid into the titration cup and ultrasonically dissolve it completely. Then add 40mL of glacial acetic acid to ensure it covers the electrode. Start stirring until the solution is well mixed. Finally, titrate it to the endpoint with 0.1mol/L perchloric acid standard titrant that has been calibrated. At the same time, conduct a blank test.

3.2 Parameter Settings

4. Results and Discussion

4.1 Experimental Results

Calculation formula

In the formula:

X represents the content of glycine, with the unit being %.

V1 and V0 are respectively the volumes of titrant consumed for titrating the sample and the blank.

7.507 is the mass of glycine corresponding to 1mL of 0.1mol/L perchloric acid.

1000 is the conversion factor

4.2 Atlas

4.3 Conclusion

The three independent test results obtained under repeatability conditions were all between 99% and 101%, and the RSD value was 0.2065, fully meeting the customer's requirements.

References

[1] Pharmacopoeia of the People's Republic of China [M]. Part II Beijing: China Medical Science and Technology Press, 2020:139-140.