Difference Between Potassium Gluconate and Potassium Citrate

Main Difference – Potassium Gluconate vs Potassium Citrate

Potassium is a chemical element which is indicated by the letter “K”. It was the first metal to be isolated by electrolysis. Potassium is very reactive and can react with various non-metal atoms to form different compounds. Potassium gluconate and Potassium citrate are two such compounds of potassium. Potassium gluconate is mainly used as a potassium supplement. Potassium citrate is mainly used as a food additive to regulate the acidity of food items. The main difference between potassium gluconate and potassium citrate is that potassium gluconate is the potassium salt of gluconic acid whereas potassium citrate is the potassium salt of citric acid.

Key Areas Covered

1. What is Potassium Gluconate
     – Definition, Chemical Structure and Properties
2. What is Potassium Citrate
     – Definition, Chemical Structure and Properties
3. What is the Difference Between Potassium Gluconate and Potassium Citrate
     – Comparison of Key Differences

Key Terms: Citric Acid, Citrate, Gluconic Acid, Potassium, Potassium Citrate, Potassium D-gluconate, Potassium Gluconate, Tripotassium Citrate

What is Potassium Gluconate

Potassium gluconate is the potassium salt of the conjugate base of the gluconic acid. It is also called as D-gluconic acid potassium salt or potassium D-gluconate. Potassium gluconate is composed of 16.69% potassium by weight. Gluconic acid is a carboxylic acid; thus, K⁺¹ ion is attached to the oxygen atom of the hydroxyl group by replacing the Hydrogen atom.  This compound exists in the solid phase. The melting point of potassium gluconate is about 175^oC.

Potassium gluconate is an odorless compound that is available as white to yellowish crystalline powder or granules. It has a slightly saline taste. It is soluble in water and is stable in air. The storage temperature of potassium gluconate is room temperature. The molecular formula of this compound is C₆H₁₁KO₇. The IUPAC name of potassium gluconate is Potassium (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhe.

Figure 1: Chemical Structure of Potassium Gluconate

Potassium gluconate is used as a mineral supplement or a sequestrant. It is sold as capsules or bulk powder. In this compound, potassium ion (K⁺¹) is bonded to the conjugate base of gluconic acid via an ionic bond. This means that there is an electrostatic attraction between K⁺¹ and gluconate anion.

What is Potassium Citrate

Potassium citrate is a potassium salt of citric acid. The chemical formula of this compound is K₃C₆H₅O₇. It is a white crystalline powder that is hygroscopic. This means potassium citrate will absorb water vapor when kept exposed to the atmosphere.

The molar mass of potassium citrate is 306.394 g/mol. The IUPAC name of potassium citrate is tripotassium citrate. It is commercially available as either a dry powder or as a liquid. Potassium citrate is odorless and has a cooling, saline taste. Potassium citrate consists of 38.28 % potassium by weight.

Figure 2: Citrate Ion- Ball and Stick Model

Potassium citrate is mainly used as a food additive to control the acidity of food items. Apart from that, this compound is used as a drug to prevent calculus. When potassium citrate is given through mouth, it is absorbed rapidly and is excreted in urine. It is helpful in reducing the pain and frequency of urination.

Difference Between Potassium Gluconate and Potassium Citrate

Definition

Potassium Gluconate:  Potassium gluconate is the potassium salt of the conjugate base of the gluconic acid.

Potassium Citrate: Potassium citrate is a potassium salt of citric acid.

Chemical Formula

Potassium Gluconate: The chemical formula of this compound is C₆H₁₁KO₇.

Potassium Citrate: The chemical formula of Potassium citrate is K₃C₆H₅O₇.

Molar Mass

Potassium Gluconate:  The molar mass of Potassium gluconate is 234.246 g/mol.

Potassium Citrate: The molar mass of potassium citrate is 306.394 g/mol.

IUPAC Name

Potassium Gluconate:  The IUPAC name of potassium gluconate is Potassium (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhe.

Potassium Citrate: The IUPAC name of potassium citrate is tripotassium citrate.

Water Absorption

Potassium Gluconate: Potassium gluconate is not hygroscopic.

Potassium Citrate: Potassium citrate is hygroscopic.

Potassium Content

Potassium Gluconate: Potassium gluconate is composed of 16.69% potassium by weight.

Potassium Citrate: Potassium citrate consists of 38.28 % potassium by weight.

Conclusion

Potassium gluconate and potassium citrate are two potassium salts. They have different applications due to the differences between chemical composition and structure of these compounds. The main difference between potassium gluconate and potassium citrate is that potassium gluconate is the potassium salt of gluconic acid whereas potassium citrate is the potassium salt of citric acid.

Reference:

1. “Potassium citrate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
2. Potassium gluconate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “Potassium gluconate” By Fvasconcellos 01:39, 8 October 2007 (UTC) – Own work (Public Domain) via Commons Wikimedia
2. “Citrate-3D-balls” By Benjah-bmm27 – Own work (Public Domain) via Commons Wikimedia