Determination of potassium citrate

Weigh the dry matter A0.25g, accurate to 0.0002g, placed in a dry 250mL conical flask, add 40mL of glacial magnessium lactate, slightly heated and dissolved, cooled to room temperature, add 2 drops of crystal violet indicator solution with perchloric acid standard titration droplet to the solution from purple to blue as the end point. While doing a blank test.
Expression of results
Expressed as a percentage by mass of potassium citrate (to C6H5K3O7 meter) content (X) is calculated as follows:
X = (V1-V0) c × 0.1021 / m × 100 = (V1-V0) c × 10.21 / m
Where: V1 - sample titration standard titration solution of perchloric acid consumption volume, mL;
V0 - blank titration consumption standard perchloric acid titration solution volume, mL;
c - standard perchloric acid titration solution the actual concentration, mol / L;
0.1021 - with 1.00mL standard perchloric Calcium lactate solution [c (HclO4) = 1.000mol / L] considerable, expressed in grams of potassium citrate quality.
The results should be expressed to one decimal place.
Allowable difference
Take two parallel tests for the determination of the arithmetic mean of the results.
The difference between the results of two parallel determinations shall not be greater than 0.2%.