DL-Malic Acid Suppliers

Formula C4H6O5
Molecular Weight 134.09

[DL-malic acid ingredient specifications]

Content
DL-malic acid should contain not less than 99.0% of DL-malic acid (C4H6O5).

Description
DL-malic acid is white crystal or crystalline powder. It is odorless or have a light, smell, taste and characteristics acid. DL-Malic Acid Suppliers

Appraisal
(1) 1 ml of a solution of DL-malic acid (1 → 20) to a test tube, adding 2 to 3 mg resorcinol, and I ml of sulfuric acid, shake, heat at 120 to 132 ° C for 5 minutes , cool, and add water to make 5 ml. Add dropwise sodium hydroxide solution (2 → 5) while cooling so that the solution was made alkaline, and adding water to make 10 ml. Light blue fluorescence observed under ultraviolet light.

(2) DL-malic acid solution (1 → 20), into a porcelain dish, and neutralized with aqueous ammonia was added 10 mg of the amino acid, and heat in a water bath for a few minutes. Was added 5 ml of sodium nitrite solution (1 → 5), warm slightly and made alkaline with sodium hydroxide solution. It turns red.

Purity
(1) Melting point: DL-malic acid, melting at 127 ~ 132 °

(2) solution clarity: When 1 g of DL-malic acid is dissolved in 20 ml of water, it should be clear.

(3) Chloride: When chloride test 1 g of DL-malic acid, the content thereof should not exceed an amount corresponding to 0.1 ml of 0.01N hydrochloric acid.

(4) arsenic: arsenic content of 0.25 g DL-malic acid when tested, its content should not exceed the millionths 4.

(5) heavy metals: 2 g of DL-malic acid was dissolved in about 40 ml of water, and 1 drop of phenolphthalein solution, aqueous ammonia solution was added dropwise until the solution became red lit. To the resulting solution was added 2 ml of dilute acetic acid, used as the test solution. This test solutions test heavy metals and its content should not be more than 20ppm.

(6) easy oxidizable substances: said take 0.1g of DL-malic acid was dissolved in 25 ml of water and 25 ml of diluted sulfuric acid (1 → 20), maintained at 20 ℃, and add 1.0 ml of 0.1N manganate potassium. The pink solutions and does not disappear within three minutes.

Residue on ignition
When the thermal gravimetric analysis, DL-malic acid, the residue should be not more than 0.05%.

Assay
Precisely weighed about 1.5 grams of DL-malic acid, and dissolved in water to make exactly 250 ml. Exactly 25 ml of the solution was then measured by titration with 0.1N sodium hydroxide (indicator: 2 drops of a phenolphthalein solution).

0.1N sodium hydroxide 1 ml = 6.704 mg of C4H6O5
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