Glycine ethyl ester hydrochloride (two)

5 Test method

Unless otherwise specified, only reagents confirmed to be analytically pure and grade 3 water specified in GB/T6682 are used in the analysis

The standard titration solutions, standard solutions for impurity determination, preparations and products used in this standard shall be prepared in accordance with GB/T 601, GB/T602 and GB/T603 unless other requirements are indicated

5.

5.

Under acidic conditions, the sample reacts with a certain amount of silver nitrate , and the excess silver nitrate is back-titrated with ammonium thiocyanate.

5.

5.

5.

5.

5.

5.

5.

Weigh about 0.

5.

The mass fraction of glycine ethyl ester hydrochloride content, the value is expressed in %, calculated according to formula (1):

Where:

V ₁ —The value of the volume of the silver nitrate standard titration solution (5.

V ₂ —The value of the volume of ammonium thiocyanate standard titration solution (5.
1.
2.
4) consumed by titration, in milliliter (mL);

c ₁ —The exact value of the concentration of silver nitrate standard titration solution, in moles per liter (mol/L);

c ₂ —The exact value of the concentration of the ammonium thiocyanate standard titration solution, in moles per liter (mol/1);

m—the value of the mass of the sample, in grams (g);

w ₂ —The mass fraction of glycine hydrochloride determined in accordance with Article 5.
2, expressed as (%);

M- Gan ethyl ester hydrochloride numerical molar mass in grams per mole (g / mol) (M = 139.
58);

1.
25—The coefficient of conversion of glycine hydrochloride into glycine ethyl ester hydrochloride
.

Take the arithmetic mean of the two parallel determination results as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.
3%
.

5.
2 Determination of glycine hydrochloride content

5.
2.
1 Method summary

In dimethyl yellow as indicator, with sodium hydroxide titration standard solution sample is titrated according to standard titration volume of sodium hydroxide solution consumed, calculate the content of glycine hydrochloride
.

5.
2.
2 Reagents

5.
2.
2.
1 Sodium hydroxide standard titration solution: c(NaOH)=0.
1mol/L;

5.
2.
2.
2 Dimethyl yellow indicator solution: 10g/L
.

5.
2.
3 Analysis steps

Weigh about 5.
0g laboratory sample, accurate to 0.
0001g, place it in a 200mL beaker, add 50mL water to dissolve it, add 5 drops of dimethyl yellow indicator solution, and titrate with sodium hydroxide standard titration solution until the solution turns from red to red Orange is the end point
.

5.
2.
4 Result calculation

The mass fraction w _{2 of the} content of glycine hydrochloride is expressed by the value and calculated according to formula (2):

Where:

V—The value of the volume of sodium hydroxide standard titration solution (5.
2.
2.
1), in milliliter (mL);

c—The exact value of the concentration of sodium hydroxide standard titration solution, the unit is moles per liter (mol/L);

M—The value of the molar mass of glycine hydrochloride, in grams per mole (g/mol) (M=111.
53);

m—The value of the mass of the sample, in grams (g)
.

Take the arithmetic average of the two parallel determination results as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.
05%
.