How to find the right Chemical Standards AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Chemical Standards
- Accredited producer
- Certified reference materials should come from a producer accredited to ISO 17034, with testing under ISO/IEC 17025. Accreditation is what regulators and auditors accept as a CRM.
- Certified value and uncertainty
- The certificate must state the value, its expanded uncertainty and traceability, typically to NIST SRMs. Without stated uncertainty you cannot build a valid calibration.
- Matrix match
- Match the standard's matrix and solvent to your method, such as dilute HNO3 for ICP or the specified solvent for GC. Matrix mismatch causes calibration bias.
- Stability and expiry
- Check both the sealed expiry and the after-opening stability. Single-use ampoules suit volatile organics. Concentration drifts through evaporation and adsorption.
- Analyte list
- For multi-component mixes, confirm every target analyte and concentration matches your method, such as an EPA method list. Missing one analyte means buying a second standard.
Brands that matter
- Inorganic Ventures: ICP and ICP-MS inorganic standards.
- SPEX CertiPrep: Inorganic and organic CRMs.
- AccuStandard: Environmental organic standards.
- Restek: GC and LC reference standards.
- High-Purity Standards: Inorganic CRMs.
- Ricca Chemical: Conductivity and pH standards.
- Hach: Standards for its water-analysis methods.
What to avoid
- Standards without a certificate stating uncertainty and traceability
- Re-using opened ampoules of volatile standards
Questions
What is the difference between a CRM and a reference material?
A CRM has a certified value with uncertainty and traceability from an accredited producer. A plain reference material may not.