GB/T 21525-2008Inorganic chemical products for industrial use - General method for determination of magnesium content by complexation titration (English PDF)

1.1

standard specifies the determination of inorganic chemical products in general method magnesium content --- complexometric titration.

1.2

This standard applies to edetate disodium (EDTA) as a complexing agent for titration of inorganic chemical products magnesium content. The standard

Quasi applicable in the test solution of magnesium ion content of 1mg ~ 200mg.

3.1 Safety Tips

Reagents used in this test method are toxic or corrosive, the operator must be careful! Such as water splashed on the skin should immediately

Flushing, severe cases should be treated immediately.

3.2 General Provisions

This standard reagents and water, did not indicate when the other requirements, refer to three analytical reagent and GB/T 6682-1992 specified water. Standard Solution, formulations and product tests required in the absence of other requirements specified according to HG/T 3696.1, HG/T 3696.3

Preparation of the provisions.

3.3 Principles

Disodium ethylenediaminetetraacetate (hereinafter referred to as EDTA) having six electron ligand in an aqueous solution with the majority of metal ion 1.1 stable soluble chelates at pH~10 conditions, adding the appropriate masking agent masking interfering ions, EDTA calcium and magnesium ions

The quantitative determination of selectivity requirements. Acidic chrome blue K, a mixed solution of naphthol green B as indicator, with EDTA standard titration solution

The total amount of calcium and magnesium titration. Under the conditions of the test solution pH~12.5, magnesium ions and hydroxide precipitates formed by the reaction, only this time with calcium EDTA Quantitative form chelates to the Cal as indicator, titration with EDTA standard solution titration of calcium. Is subtracted from the total amount of calcium and magnesium in calcium

Content to calculate the magnesium content.

3.4 Reagents

3.4.1 triethanolamine solution

1 + 1;

3.4.2 triethanolamine solution

1 + 3;

3.4.3

potassium hydroxide solution.200g/L;

3.4.4

ammonia - ammonium chloride buffer solution A. pH~10;

3.4.5

disodium ethylenediaminetetraacetate (EDTA) titration solution standard solution. Ba (EDTA) ~0.02mol/L;

3.4.6

Acid chrome blue K- naphthol green B mixed indicator solution. dissolve 0.3g of acid chrome blue K and naphthol green B 0.75g triethylamine in 100mL

Alcohol amine solution (3.4.1) in.

GB/T 19282-2014 | GB/T 23769-2009 | GB/T 21354-2008 | GB/T 30903-2026 | GB/T 23834.7-2026 | […]