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
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 -
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 -
Method
Calculating Molarity: Mass, Molecular Weight, Volume and Common Pitfalls
Molarity (mol/L) is calculated using mass (g), molecular weight (g/mol), and volume (L). The formula is M = (mass / MW) / volume. Common errors include incorrect unit conversion, ignoring solute hydration, and inaccurate volume measurement. Always verify units and use calibrated equipment.
Jun 2, 2026 · 4 min read -
Supplier-news
Understanding HTS and Tariff Codes for Chemical Imports: A Guide for UK and EU-Based Researchers
Customs Harmonised Tariff Schedule (HTS) codes are essential for classifying chemical imports under UK and EU trade regulations. Accurate HTS codes ensure compliance with REACH, TSCA, and GHS, and prevent delays or penalties. Codes vary by chemical structure, purity, and intended use. Always verify with national customs authorities or a qualified customs broker.
Jun 1, 2026 · 5 min read -
Regulatory
IATA/ADR Transport Classifications for Laboratory Chemicals
Laboratory chemicals are subject to IATA (air) and ADR (road) regulations based on hazard classification. Key categories include flammable liquids (Class 3), corrosives (Class 8), and toxic substances (Class 6.1). Proper classification requires evaluation of flash point, toxicity (LD50), and reactivity. Labels, packaging, and documentation must comply with UN recommendations and regulatory standards.
May 31, 2026 · 5 min read -
Regulatory
Cold-chain shipping regulations for biological reagents
Biological reagents must be shipped under controlled temperature conditions to maintain stability and integrity. Regulations vary by region, with EU and US frameworks requiring compliance with ISO 11607, REACH, and TSCA. Temperature monitoring via validated data loggers and adherence to GHS labelling are mandatory. Shipping durations and storage conditions depend on the reagent type and stability data.
May 30, 2026 · 5 min read -
Applications
Pharmacopoeia Grades (USP/EP/BP): What They Mean for Procurement
Pharmacopoeia grades (USP, EP, BP) denote substances meeting strict quality, purity, and testing standards for pharmaceutical use. Procurement teams must verify compliance with relevant monographs, ensure traceable CoA and SDS, and confirm batch consistency. These grades are essential for regulatory submissions and clinical trial material sourcing.
May 29, 2026 · 5 min read