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251275

Sigma-Aldrich

Citric acid

ACS reagent, ≥99.5%

Synonym(s):

2-Hydroxy-1,2,3-propanetricarboxylic acid, 2-Hydroxypropan-1,2,3-tricarboxylic acid

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About This Item

Linear Formula:
HOC(COOH)(CH2COOH)2
CAS Number:
Molecular Weight:
192.12
Beilstein:
782061
EC Number:
MDL number:
UNSPSC Code:
12352100
eCl@ss:
39021801
PubChem Substance ID:
NACRES:
NA.21
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grade

ACS reagent

Quality Level

Assay

≥99.5%

form

crystals

expl. lim.

8 %, 65 °F

impurities

Substances carbonizable by hot sulfuric acid, passes test

ign. residue

≤0.02%

pKa 

(1) 3.13, (2) 4.76, (3) 6.4

mp

153-159 °C (lit.)

anion traces

chloride (Cl-): ≤0.001%
oxalate (C2O42-): passes test (limit about 0.003%)
phosphate (PO43-): ≤0.001%
sulfate (SO42-): ≤0.002%

cation traces

Fe: ≤3 ppm
Pb: ≤2 ppm

functional group

carboxylic acid
hydroxyl

SMILES string

OC(=O)CC(O)(CC(O)=O)C(O)=O

InChI

1S/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)

InChI key

KRKNYBCHXYNGOX-UHFFFAOYSA-N

Gene Information

human ... SRC(6714)

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General description

Citric acid is a weak organic acid that is commonly used for pH adjustment, as a chelating agent, as a buffering agent, derivatization and as starting material for the synthesis of citrate esters and other compounds.[1]

Application

Citric acid has been used to prepare:
  • Phosphate citrate buffer for use in enzyme-linked immunosorbent assay.[2]
  • Citrate-stabilized ceria aqueous sol, which was employed in the synthesis of cerium oxide nanoparticles.[3]
  • Citric acid-Na2HPO4-buffered stock solution for use in the determination of fecal urease activity.[4]
  • Anticoagulant citrate dextrose solution A (ACD-A), which is employed during the isolation of blood-derived endothelial progenitor cells.[5]

Citric acid has also been used:
  • In a novel process which allows controlling of the particle size during the synthesis of palladium cuboctahedrons.[6]
  • To prepare citric acid-derived carbon nanodots (CNDs) by bottom-up carbonization method.[7]
  • As a bi-component chelating agent for the synthesis of Li4Ti5O12 (lithium titanate oxide) by a novel sol–gel method.[8]

Legal Information

Redi-Dri is a trademark of Sigma-Aldrich Co. LLC

Pictograms

Exclamation mark

Signal Word

Warning

Hazard Statements

Hazard Classifications

Eye Irrit. 2 - STOT SE 3

Target Organs

Respiratory system

Storage Class Code

11 - Combustible Solids

WGK

WGK 1

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Citric Acid
Lopez-Garcia, R
Kirk-Othmer Encyclopedia of Chemical Technology (2010)
Cerium fluoride nanoparticles protect cells against oxidative stress.
Shcherbakov AB, et al.
Materials Science & Engineering. C, Materials For Biological Applications, 50, 151-159 (2015)
Investigation of Size-Dependent Plasmonic and Catalytic Properties of Metallic Nanocrystals Enabled by Size Control with HCl Oxidative Etching.
Li B, et al.
Small, 8(11), 1710-1716 (2012)
Juan M Melero-Martin et al.
Methods in enzymology, 445, 303-329 (2008-11-22)
Rapid and complete vascularization of ischemic tissues and thick engineered tissues is likely to require vasculogenesis. Therefore, the search for clinically relevant sources of vasculogenic cells and the subsequent development of experimental models of vasculogenesis is of utmost importance. Here
Beyond bottom-up carbon nanodots: Citric-acid derived organic molecules.
Zhu S, et al.
Nano Today (2015)

Protocols

SEC-MS protocol for rapid glycoprofiling of monoclonal antibodies with antibody purification and mass spectrometer calibration.

SEC-MS protocol for rapid glycoprofiling of monoclonal antibodies with antibody purification and mass spectrometer calibration.

SEC-MS protocol for rapid glycoprofiling of monoclonal antibodies with antibody purification and mass spectrometer calibration.

SEC-MS protocol for rapid glycoprofiling of monoclonal antibodies with antibody purification and mass spectrometer calibration.

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Questions

1–4 of 4 Questions  
  1. How can I determine the shelf life / expiration / retest date of this product?

    1 answer
    1. If this product has an expiration or retest date, it will be shown on the Certificate of Analysis (COA, CofA). If there is no retest or expiration date listed on the product's COA, we do not have suitable stability data to determine a shelf life. For these products, the only date on the COA will be the release date; a retest, expiration, or use-by-date will not be displayed.
      For all products, we recommend handling per defined conditions as printed in our product literature and website product descriptions. We recommend that products should be routinely inspected by customers to ensure they perform as expected.
      For products without retest or expiration dates, our standard warranty of 1 year from the date of shipment is applicable.
      For more information, please refer to the Product Dating Information document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/449/386/product-dating-information-mk.pdf

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  2. How is shipping temperature determined? And how is it related to the product storage temperature?

    1 answer
    1. Products may be shipped at a different temperature than the recommended long-term storage temperature. If the product quality is sensitive to short-term exposure to conditions other than the recommended long-term storage, it will be shipped on wet or dry-ice. If the product quality is NOT affected by short-term exposure to conditions other than the recommended long-term storage, it will be shipped at ambient temperature. As shipping routes are configured for minimum transit times, shipping at ambient temperature helps control shipping costs for our customers. For more information, please refer to the Storage and Transport Conditions document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/316/622/storage-transport-conditions-mk.pdf

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  3. Technical question: is this product sourced in the EU. Is it for RUO.

    1 answer
    1. Yes, this product is intended for research use only. The country of origin may vary lot to lot.

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  4. Do you have a recommendation for an expiry date after opening this reagent (storage in dry place at RT)?

    1 answer
    1. This product does not contain an expiration date or recommended retest date. Products with no expiration date or recommended retest date should be routinely inspected by customers to ensure they perform as expected. These products are also subject to a one year warranty from the date of shipment. For more information you may access the "Product Dating Information" document under "ADDITIONAL USEFUL DOCUMENTS ABOUT OUR PRODUCTS" at the bottom of the Quality Services page with this link: https://www.sigmaaldrich.com/life-science/quality-and-regulatory-management/quality-services.

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