CITRIC ACID,China UC price supplier

SYNONYMS

INS No. 330

DEFINITION

Citric acid may be produced by recovery from sources such as lemon or pineapple juice or fermentation of carbohydrate solutions or other suitable media using  Candida  spp. or non-toxicogenic strains of  Aspergillus  niger

Chemical names

2-hydroxy-1,2,3-propanetricarboxylic acid

C.A.S. number

77-92-9 (anhydrous)

5949-29-1 (monohydrate)

Chemical formula

C ₆  H ₈  O ₇  (anhydrous)

C ₆  H ₈  O ₇  · H ₂  O (monohydrate)

Structural formula

Anhydrous Monohydrate

Formula weight

192.13 (anhydrous)

210.14 (monohydrate)

Assay

Not less than 99.5% and not more than 100.5% on the anhydrous basis

DESCRIPTION

White or colourless, odourless, crystalline solid; the monohydrate form effloresces in dry air

FUNCTIONAL USES

Acidulant; sequestrant; antioxidant synergist; flavouring agent (see "Flavouring agents" monograph)

CHARACTERISTICS

IDENTIFICATION

Solubility  (Vol.4)

Very soluble in water; freely soluble in ethanol; slightly soluble in ether

Test for citrate (Vol. 4)

Passes test

PURITY

Water  (Vol. 4)

Anhydrous: Not more than 0.5% (Karl Fischer Method)

Monohydrate: Not less than 7.5% and not more than 8.8% (Karl Fischer

Method)

Sulfated ash (Vol. 4)

Not more than 0.05%

Oxalate  (Vol. 4)

Not more than 100 mg/kg

Test  1.0 g of the sample by the Oxalate Limit Test (Volume 4). Measure absorbance at 520 nm in a  10 mm cell. The test solution should have less than 0.023 absorbance units.

Sulfates (Vol. 4)

Not more than 150 mg/kg

Test  20 g of the sample by the Sulfates Limit Test (Volume 4) using 6.0 ml of 0.01N sulfuric acid in the standard

Readily carbonizable substances

Heat  1.0 g of sample with 10 ml of 98% sulfuric acid in a water bath at 90 ± 1 ^o  for 60 min. No colour darker than MatchingFluid K (25 ^o ) should be produced (not more than 0.5 absorbance units at 470 nm in a  10 mm cell).

Lead  (Vol. 4)

Not more than 0.5 mg/kg

Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”

METHOD OF

ASSAY

Weigh, to the nearest mg,  2.5 g of the sample and place in a tared flask. Dissolve in 40 ml of water and titrate with 1 N sodium hydroxide, using phenolphthalein TS as the indicator. Each ml of 1 N sodium hydroxide is equivalent to 64.04 mg of C ₆ H ₈ O ₇ .