Knowledge hub
Articles from the Molekula editorial team
Coverage of chemistry, regulatory updates, methods, supply-chain insight, and product spotlights. New articles published daily.
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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 -
Applications
Sodium chloride in cell-culture media and physiological buffers
Sodium chloride (NaCl) is a critical electrolyte in cell-culture media and physiological buffers, typically present at 137–140 mM. It maintains osmotic balance, supports ion transport, and stabilises protein structure. High-purity grades (ACS, USP, EP) are required for cell culture, with endotoxin levels < 0.1 EU/mL. Reagent-grade NaCl is unsuitable for biological applications.
Jun 18, 2026 · 4 min read -
Method-comparison
Acetone as a solvent: when to choose it over methanol or ethanol
Acetone is a polar aprotic solvent with high solubility for organic compounds, low viscosity, and rapid evaporation. It is preferred over methanol and ethanol in applications requiring fast drying, minimal hydrogen bonding interference, or high solubility for non-polar compounds. Its lower toxicity and higher boiling point than ethanol make it suitable for lab-scale extractions and cleaning. However, it is more flammable and less biocompatible than ethanol.
Jun 17, 2026 · 4 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 -
Applications
EDTA Chelation Chemistry and Applications Across Biology, Food and Analytical Chemistry
EDTA (ethylenediaminetetraacetic acid, CAS 60-00-4) is a versatile chelating agent used extensively in biological, food and analytical systems. It forms stable complexes with divalent and trivalent metal ions (e.g., Ca²⁺, Mg²⁺, Fe³⁺), with stability constants (log K) ranging from 10.3 to 18.6. Applications include enzyme inhibition, food preservation, and metal ion standardisation in analytical methods.
Jun 15, 2026 · 5 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 -
Applications
Common Buffers for Protein Purification: HEPES, Tris, PIPES, and MES
HEPES, Tris, PIPES, and MES are widely used buffers in protein purification due to their stability, buffering capacity near physiological pH, and compatibility with downstream applications. HEPES (pKa 7.5) is preferred for long-term stability; Tris (pKa 8.1) is cost-effective but can degrade; PIPES (pKa 6.8) and MES (pKa 6.1) are suitable for lower pH applications. All are available in high-purity grades (ACS, USP, EP) with certified CoA and SDS.
Jun 13, 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-comparison
How TCEP differs from DTT as a disulfide reducing agent
TCEP (tris(2-carboxyethyl)phosphine) and DTT (dithiothreitol) are both disulfide reducing agents used in biochemical and chemical applications. TCEP is more stable in aqueous solutions and at higher pH, resistant to oxidation, and effective under denaturing conditions. DTT is less stable, prone to oxidation, and less effective above pH 7.5. Both are used in protein denaturation, sample preparation, and redox studies.
Jun 9, 2026 · 4 min read -
Applications
Uses of DTT (dithiothreitol) in proteomics and SDS-PAGE sample preparation
DTT (dithiothreitol, CAS 3483-12-3) is a reducing agent essential in proteomics and SDS-PAGE sample preparation. It breaks disulphide bonds in proteins, preventing aggregation and ensuring complete denaturation. Typically used at 1–5 mM final concentration, DTT is preferred over β-mercaptoethanol due to its lower odour and higher stability. It is compatible with downstream applications including mass spectrometry and ELISA.
Jun 8, 2026 · 4 min read -
Applications
Cryopreservation Buffers and Stabilisers: Key Components for Biological Sample Integrity
Cryopreservation buffers and stabilisers are essential for maintaining the structural and functional integrity of biological samples during freezing and thawing. Key components include cryoprotectants (e.g., DMSO, glycerol), buffering agents (e.g., HEPES, Tris), and stabilising excipients (e.g., sucrose, trehalose). Optimal formulations depend on cell type, storage duration, and downstream application. Standardised protocols using validated reagents ensure reproducibility and compliance with ISO, GHS, and USP/EP/BP guidelines.
Jun 7, 2026 · 6 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