All Photos(7)



Potassium phosphate monobasic

anhydrous, free-flowing, Redi-Dri, ACS reagent, ≥99%

prim.-Potassium phosphate, Monopotassium phosphate, Potassium dihydrogen phosphate
Linear Formula:
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


ACS reagent

product line









≤0.01% Insoluble matter


≤0.2% loss on drying, 105°C


4.1-4.5 (25 °C, 5%)

pKa (25 °C)

(1) 2.15, (2) 6.82, (3) 12.38 (phosphoric acid)


252.6 °C (lit.)


2.338 g/mL at 25 °C (lit.)

anion traces

chloride (Cl-): ≤0.001%
sulfate (SO42-): ≤0.003%

cation traces

Fe: ≤0.002%
Na: ≤0.005%
heavy metals: ≤0.001% (by ICP)

SMILES string




InChI key


Looking for similar products? Visit Product Comparison Guide

Related Categories

General description

Potassium phosphate monobasic (monopotassium orthophosphate) is a water soluble inorganic salt. Its standard enthalpy of formation has been reported to be −376.1 kcalmol-1. It acts a starting material in the synthesis of potassium metaphosphate.


Potassium phosphate monobasic has been used in the preparation of phosphate buffer and phosphate buffered saline (PBS). It has also been used in the preparation of PEG1000 (polyethylene glycol)/potassium phosphate aqueous two-phase systems (ATPS).


1, 2.5 kg in poly bottle
500 g in poly bottle

Features and Benefits

  • Increased efficiency – Eliminate time and effort of loosening hardened powders
  • Safety – Avoid risks of using tools of force to break up clumps
  • Economy – Faster preparation and solvation increase productivity and reduce costs
  • Assured quality – Excellent, expert-tested quality with no anti-caking agents
  • Flexible volumes – Available from research amounts to scale-up quantities

Legal Information

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

Storage Class Code

13 - Non Combustible Solids



Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

More Documents

Quotes and Ordering

  1. How does Redi-Dri help keep salts and buffers free-flowing?

    Redi-Dri products are specially handled and the bottle is specially designed to ensure that the product will remain dry without adding impurities or additives to the product. Ensuring that you receive the highest quality material that is easy to handle.

  2. Are there any special storage conditions that must be maintained?

    No, Redi-Dri products can be stored under the same conditions as the equivalent non-Redi-Dri products.

  3. How long will material remain free-flowing after it is opened?

    While the exact amount of time your material will remain free-flowing can vary, this largely depends on the ambient storage conditions and how many times it is opened.

Wenchong Sun et al.
Experimental neurobiology, 29(5), 356-375 (2020-11-07)
Dexmedetomidine (DEX) has neuroprotective effects and its efficacy was determined in propofol-treated pups. Postnatal day (P) 7 rats were exposed to propofol and DEX to investigate the induced apoptosis-related gene expression. Furthermore, synaptic structural changes at the cellular level were
Venkata Ramana Vaka et al.
American journal of physiology. Regulatory, integrative and comparative physiology, 318(2), R256-R262 (2019-11-14)
Preeclampsia (PE) is characterized by new-onset hypertension that usually occurs in the third trimester of pregnancy and is associated with oxidative stress and angiotensin II type 1 receptor agonistic autoantibodies (AT1-AAs). Inhibition of the AT1-AAs in the reduced uterine perfusion
Mao Taketani et al.
Nature biotechnology, 38(8), 962-969 (2020-04-02)
Bacteroides thetaiotaomicron is a human-associated bacterium that holds promise for delivery of therapies in the gut microbiome1. Therapeutic bacteria would benefit from the ability to turn on different programs of gene expression in response to conditions inside and outside of
Lina M González et al.
Nature chemical biology, 16(2), 126-133 (2019-12-04)
Materials can be made multifunctional by embedding them with living cells that perform sensing, synthesis, energy production, and physical movement. A challenge is that the conditions needed for living cells are not conducive to materials processing and require continuous water
Venkata Ramana Vaka et al.
American journal of physiology. Regulatory, integrative and comparative physiology, 316(5), R441-R447 (2019-02-28)
Preeclampsia (PE) is characterized by new-onset hypertension during pregnancy and is associated with immune activation and placental oxidative stress. Mitochondrial dysfunction is a major source of oxidative stress and may play a role in the pathology of PE. We (Vaka


Redi-Dri™ – The World of Free-flowing Hygroscopic Products

Redi-Dri™ prevents hygroscopic powders, such as inorganic salts, from absorbing moisture and forming clumps, leaving the salts free-flowing every time.


USP Dissolution Testing Method (HPLC) for Folic Acid Tablets Using a Monolith Column and UV detection

Folic acid or folate is classified as a B vitamin (B9). Folic acid is synthetically produced, and used in fortified foods and supplements. Folate is converted by humans to dihydrofolate (dihydrofolic acid), tetrahydrofolate (tetrahydrofolic acid), and other derivatives, which have various biological activities.

HPLC Analysis of Aswagandha Extract on Discovery® C18

Separation of Withanoside IV; Withanoside V; Withaferin A; 12-Deoxywithastramonolide; Withanolide A; Withanolide B

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service