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CHM.201198 - Potassium Phosphate Monobasic - ACS reag., ≥99.0% - CAS: 7778-77-0
Potassium phosphate monobasic (KH₂PO₄), with the Chemical Abstracts Service (CAS) number 7778-77-0, is a widely used chemical in molecular biology due to its role as a buffering agent and source of phosphate ions. It is an inorganic salt that provides stability to biological systems and is essential for various laboratory protocols. Below is a detailed overview of the molecular biology applications of potassium phosphate monobasic:
1. Buffer Preparation
Potassium phosphate monobasic is a key component of phosphate buffers, which are widely used in molecular biology to maintain stable pH conditions. Examples include:
  • Phosphate-Buffered Saline (PBS): A common buffer used for cell washing, immunohistochemistry, and immunofluorescence assays. PBS typically contains potassium phosphate monobasic along with sodium chloride and potassium chloride.
  • Lysis Buffers: Used for cell lysis and protein extraction, where maintaining a stable pH is critical for preserving protein integrity.
  • Enzyme Assays: Potassium phosphate buffers are used in enzymatic reactions to maintain optimal pH and ionic strength.
2. Cell Culture Media
Potassium phosphate monobasic is used in cell culture media formulations to provide phosphate ions, which are essential for cell growth and metabolism. It helps:
  • Maintain Osmotic Balance: By contributing to the ionic strength of the medium.
  • Support Nutrient Uptake: Phosphate ions are required for the synthesis of nucleic acids, ATP, and other cellular components.
3. Nucleic Acid Extraction and Purification
Potassium phosphate monobasic is used in nucleic acid extraction protocols to stabilize pH and provide phosphate ions. Applications include:
  • DNA Extraction: Used in lysis buffers to maintain pH and ionic strength during cell lysis and DNA precipitation.
  • RNA Extraction: Helps stabilize RNA during isolation and purification steps.
4. Protein Crystallization
Potassium phosphate monobasic is used in protein crystallization screens to create conditions that promote the formation of protein crystals. It helps:
  • Stabilize Protein Structure: By providing a buffered environment.
  • Promote Crystal Growth: By optimizing ionic strength and pH.
5. Electrophoresis
Potassium phosphate monobasic is used in the preparation of electrophoresis buffers for the separation of nucleic acids and proteins. Examples include:
  • Agarose Gel Electrophoresis: Used in the running buffer to maintain pH and ionic strength.
  • Polyacrylamide Gel Electrophoresis (PAGE): Used in the preparation of gel buffers for protein separation.
6. Enzyme Reactions
Potassium phosphate monobasic is used in enzymatic reactions to provide a stable pH environment and phosphate ions, which are often required as cofactors or substrates. Examples include:
  • Kinase Assays: Phosphate ions are essential for kinase activity.
  • Phosphatase Assays: Used to study the activity of phosphatases, which remove phosphate groups from substrates.
7. Molecular Cloning
Potassium phosphate monobasic is used in molecular cloning protocols to stabilize pH and provide phosphate ions. Applications include:
  • Transformation Buffers: Used to prepare competent cells for DNA uptake.
  • Ligation Reactions: Helps maintain optimal conditions for DNA ligase activity.
8. Safety and Handling
  • Toxicity: Potassium phosphate monobasic is generally considered low toxicity, but it should be handled with care to avoid inhalation or contact with skin and eyes.
  • Storage: Store in a cool, dry place in tightly sealed containers to prevent moisture absorption.
  • Disposal: Dispose of according to local regulations for chemical waste.
9. Advantages of Potassium Phosphate Monobasic
  • Buffering Capacity: Effective at maintaining pH in the physiological range (pH 6.5–7.5).
  • Compatibility: Compatible with proteins, nucleic acids, and enzymes.
  • Cost-Effective: Inexpensive and widely available.
10. Limitations
  • Precipitation: Can form insoluble precipitates with divalent cations (e.g., Ca²⁺, Mg²⁺) at high concentrations.
  • pH Sensitivity: Buffering capacity is limited to the pH range of 6.5–7.5.

CHM.201198 - Potassium Phosphate Monobasic - ACS reag., ≥99.0% - CAS: 7778-77-0

SKU: CHM.201198
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  • 1. General Information

    • Chemical Formula: KH₂PO₄

    • Molecular Weight: 136.09 g/mol

    • CAS Number: 7778-77-0

    • Grade: ACS Reagent

    • Purity: ≥99%

    2. Physical Properties

    • Appearance: White crystalline powder or granules.

    • Odor: Odorless.

    • Density: 2.34 g/cm³ (at 20°C).

    • Melting Point: 252.6°C (486.7°F).

    • Solubility: Highly soluble in water (222 g/L at 20°C). Insoluble in ethanol and other organic solvents.

    • pH: Acidic (pH ~4.4–4.9 in 1% aqueous solution).

    3. Chemical Properties

    • Hygroscopicity: Potassium phosphate monobasic is mildly hygroscopic, absorbing moisture from the air under high humidity conditions.

    • Reactivity:

      • Reacts with strong bases to form dibasic potassium phosphate (K₂HPO₄) and tribasic potassium phosphate (K₃PO₄).

      • Forms insoluble precipitates with divalent cations (e.g., Ca²⁺, Mg²⁺) at high concentrations.

    • Stability: Stable under normal conditions but may decompose at high temperatures (>252.6°C) to produce potassium metaphosphate (KPO₃) and water (H₂O).

    4. Purity and Impurities

    • Purity: ≥99% KH₂PO₄.

    • Impurities:

      • Loss on Drying: ≤0.2% (indicating moisture content).

      • Insoluble Matter: ≤0.01%.

      • Chloride (Cl⁻): ≤0.003%.

      • Sulfate (SO₄²⁻): ≤0.005%.

      • Heavy Metals (as Pb): ≤5 ppm.

      • Iron (Fe): ≤0.001%.

      • Sodium (Na): ≤0.02%.

    5. Analytical Methods

    The purity and quality of potassium phosphate monobasic can be assessed using:

    • Titration: Acid-base titration to determine phosphate content.

    • Ion Chromatography: To detect and quantify chloride, sulfate, and other anions.

    • Atomic Absorption Spectroscopy (AAS): To measure heavy metal impurities.

    • Loss on Drying (LOD): To determine moisture content.

    6. Storage and Handling

    • Storage Conditions: Store in a cool, dry place in tightly sealed containers to prevent absorption of moisture.

    • Shelf Life: Indefinite if stored properly.

    • Handling Precautions:

      • Use personal protective equipment (PPE), including gloves, lab coats, and safety goggles.

      • Avoid inhalation of dust and contact with skin and eyes.

    7. Safety Information

    • Toxicity: Potassium phosphate monobasic is generally considered low toxicity, but it may cause irritation to the skin, eyes, and respiratory tract.

    • Flammability: Non-flammable.

    • Environmental Impact: Generally considered environmentally benign, but high concentrations in water bodies can lead to eutrophication.

    8. Applications

    Potassium phosphate monobasic is used in a wide range of applications, including:

    • Molecular Biology: Buffer preparation, cell culture media, and nucleic acid extraction.

    • Pharmaceuticals: As an excipient in tablet formulations and intravenous solutions.

    • Food Industry: As a pH regulator, emulsifier, and nutrient supplement.

    • Water Treatment: For pH adjustment and corrosion inhibition.

    • Chemical Synthesis: As a source of phosphate ions in organic and inorganic reactions.

    9. Regulatory Compliance

    Potassium phosphate monobasic complies with various regulatory standards, including:

    • ACS Reagent Grade: Meets the specifications of the American Chemical Society for use in analytical chemistry.

    • FDA (Food and Drug Administration): Approved for use in food processing and pharmaceuticals.

    • USP/NF: United States Pharmacopeia/National Formulary.

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