Glycine (Glycine) for Industrial Use (2)

4 Test method

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Some test procedures specified by the test method may lead to dangerous situations

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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 the test methods are prepared in accordance with GB/T601, GB/T602, and GB/T603 unless other requirements are specified

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The sample uses formic acid as auxiliary solvent, glacial acetic acid as solvent, crystal violet as indicator, and titration with perchloric acid standard titration solution.

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4 Result calculation

The mass fraction w _{1 of} glycine , expressed in %, calculated according to formula (1):

Where:

V ₁ —The value of the volume of the perchloric acid standard titration solution (4.
3.
2.
3) consumed by the sample, in milliliters (mL);

V ₂ ——The value of the volume of the perchloric acid standard titration solution (4.
3.
2.
3) consumed in the blank test, in milliliter (mL);

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

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

M — The value of the molar mass of glycine , in grams per mole (g/mol) (M=75.
07)
.

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%
.

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4 Determination of chloride content

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1 Method summary

The sample uses potassium chromate as an indicator and is titrated with a silver nitrate standard titration solution to calculate the chloride content in the sample
.

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2 Reagents

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2.
1 Silver nitrate standard titration solution: c(AgNO ₃ )=0.
05 mol/L;

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2.
2 Potassium chromate solution: 100g/L, weigh 10g potassium chromate , accurate to 0.
01g, dissolve it in a small amount of water containing 1 drop of sodium hydroxide solution (100g/L), and dilute to 100mL
.

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3 Analysis steps

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1 Weigh about 1g laboratory sample as the test material, accurate to 0.
0002g, place it in a 250mL conical flask, add 50mL water to dissolve, add 7 drops of potassium chromate solution, and titrate with silver nitrate standard titration solution to brick red For the end
.

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2 At the same time of measurement, perform a blank test with the same amount of reagent solution without adding samples according to the same steps as the measurement
.

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4 Result calculation

The mass fraction w _{2 of} chloride (calculated as Cl) , the value is expressed in %, calculated according to formula (2):

Where:

V ₁ —The value of the volume of the standard silver nitrate titration solution (4.
4.
2.
1) consumed by the sample, in milliliters (mL);

V ₂ —The value of the volume of the silver nitrate standard titration solution (4.
4.
2.
1) consumed in the blank test, in milliliter (mL);

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

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

M—The value of the molar mass of chlorine, in grams per mole (g/mol) (M=35.
45)
.

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.
03%
.

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5 Determination of loss on drying

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1 Analysis steps

Weigh about 1g laboratory sample as a sample, accurate to 0.
0002g, and place it in a weighing bottle that has been dried at (105±2)℃ to a constant mass, and spread it into a layer with a thickness of less than 5mm.
) Dried at ℃ for 3h, placed in a desiccator to cool for 30min, and weighed
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Keep the dried substance A for the determination of the content of aminoacetic acid
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2 Result calculation

The mass fraction of loss on drying w ₃ , the value is expressed in %, calculated according to formula (3):

Where:

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

m ₁ —The value of the mass of the sample after drying, 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%
.

Related Links: Glycine (Glycine) for Industrial Use (1)