Knowledge hub
Articles from the Molekula editorial team
Coverage of chemistry, regulatory updates, methods, supply-chain insight, and product spotlights. New articles published daily.
-
Method
How to Choose Between USP, ACS, FCC and BP Grades for the Same Chemical
When selecting a chemical grade—USP, ACS, FCC or BP—consider the intended application, regulatory requirements, and purity specifications. USP grades meet pharmacopeial standards for pharmaceutical use; ACS for general laboratory use; FCC for food-grade applications; BP for UK regulatory compliance. Purity, impurity profiles, and documentation (CoA, SDS) vary significantly between grades.
Jun 24, 2026 · 5 min read -
Method
Acid Chlorides: Production, Purification, and Supply Considerations
Acid chlorides are vital intermediates in organic synthesis, particularly in pharmaceutical and fine chemical manufacturing. They are typically produced from carboxylic acids using thionyl chloride (SOCl₂), oxalyl chloride, or phosphorus trichloride (PCl₃). Purification often involves distillation under inert atmosphere; yields vary by reagent and substrate. Supply considerations include handling hazards, stability, and regulatory compliance under REACH, GHS, and TSCA. Storage requires anhydrous conditions and inert atmosphere.
Jun 23, 2026 · 4 min read -
Method
Phosphate-Buffered Saline (PBS): Formulations, pH, and What Really Matters
PBS is a widely used buffer in biological research, with standard formulations based on Na2HPO4 and KH2PO4. The pH is typically maintained at 7.4, but varies with temperature and ionic strength. Key factors include buffer concentration (137 mM NaCl, 2.7 mM KCl, 10 mM phosphate), pH stability across temperature, and compatibility with downstream applications. Proper storage and handling are essential to prevent microbial contamination and pH drift.
Jun 22, 2026 · 5 min read -
Method
Grignard Reagents: Preparation, Handling, and Scafell Organics Capabilities
Grignard reagents (RMgX) are essential organomagnesium compounds used in C–C bond formation. They are prepared from alkyl/aryl halides and magnesium metal under anhydrous conditions. Handling requires strict exclusion of moisture and oxygen. Scafell Organics offers high-purity Grignard reagents in various formats, including pre-formed solutions and custom synthesis services, supporting pharmaceutical and synthetic chemistry applications.
Jun 21, 2026 · 4 min read -
Method
Boronic Acids in Suzuki-Miyaura Coupling: Handling, Storage, and Impurities
Boronic acids are pivotal in Suzuki-Miyaura cross-coupling reactions, enabling C–C bond formation under mild conditions. Key considerations include moisture sensitivity, storage stability (typically 2–5 years at −20 °C), and impurity profiles—especially boronate esters and boric acid—requiring HPLC or NMR analysis. Impurities can reduce yield and reproducibility, particularly in pharmaceutical applications.
Jun 20, 2026 · 4 min read -
Method
Lithium chloride in molecular biology: RNA precipitation and beyond
Lithium chloride (LiCl) is a critical reagent in molecular biology, primarily used for RNA precipitation due to its high ionic strength and ability to disrupt hydrogen bonding. It is effective at concentrations of 0.3–1.0 M, with optimal recovery at 0.5 M. LiCl is also used in protein purification and nucleic acid fractionation. Its use is supported by ISO and REACH compliance, and it is available in ACS and FCC grades. Safety data (SDS) and CoA are provided by suppliers.
Jun 19, 2026 · 5 min read -
Method
Sucrose Density-Gradient Centrifugation: Practical Tips for Optimal Results
Sucrose density-gradient centrifugation separates macromolecules by buoyant density. Key factors include gradient preparation accuracy, rotor type, temperature control, and sample loading. Use high-purity sucrose (≥99.5%) and ensure gradient homogeneity to avoid band distortion. Centrifugation times and speeds depend on the target molecule (e.g., 100,000 × g for 2–4 hours for ribosomes). Always validate gradients with marker proteins or nucleic acids.
Jun 16, 2026 · 4 min read -
Method
Sodium Dodecyl Sulfate (SDS) in Protein Gel Electrophoresis: A Technical Overview
SDS is a critical detergent in SDS-PAGE, denaturing proteins and imparting uniform negative charge. It enables separation by molecular weight, with typical concentrations of 0.1–1% (w/v) in running buffers and gels. SDS is used in conjunction with reducing agents like DTT or TCEP to break disulfide bonds. Its compatibility with downstream applications such as Western blotting and mass spectrometry is well established.
Jun 14, 2026 · 4 min read -
Method
Imidazole as a buffer and metal-affinity elution reagent: practical considerations for biochemical applications
Imidazole is widely used in biochemical workflows as a pH buffer and for eluting histidine-tagged proteins from Ni-NTA resins. It is effective between pH 6.5 and 8.5, with a pKa of 6.95 at 25 °C. Typical concentrations range from 100 to 500 mM in elution buffers. Its low toxicity and compatibility with downstream applications make it a standard reagent in protein purification and enzymatic assays.
Jun 12, 2026 · 5 min read -
Method
Filter Sterilisation of Biochemical Buffers: Choosing Pore Size and Material
Filter sterilisation of biochemical buffers requires selecting a pore size of 0.22 µm for standard sterilisation and 0.1 µm for ultrafiltration. Membrane materials such as PVDF, PES, and nylon are commonly used, with PVDF offering superior chemical resistance and low protein binding. Compatibility with buffer pH, solvents, and intended application is critical.
Jun 6, 2026 · 5 min read -
Method
Calibrating pH Meters for Chemistry and Biology Buffers
pH meters must be calibrated using certified buffer solutions (e.g., pH 4.01, 7.00, 10.01) at the temperature of use to ensure accuracy. Calibration should be performed before each use and after electrode storage. Temperature compensation is essential; most meters have automatic temperature compensation (ATC) via a built-in sensor. For biological and chemical applications, calibration with at least two points is standard. Repeated calibration with the same buffer may indicate electrode drift or contamination.
Jun 5, 2026 · 5 min read -
Method
Diluting Concentrated Stocks: C1V1 = C2V2 and Serial Dilutions
To dilute concentrated stocks accurately, use the formula C1V1 = C2V2, where C1 and V1 are the initial concentration and volume, and C2 and V2 are the final concentration and volume. For serial dilutions, apply the formula iteratively across multiple steps, ensuring consistent dilution factors. Precision depends on calibrated equipment and correct technique.
Jun 3, 2026 · 4 min read