Chemical analysis is only considered valid when the analytical method has been properly validated prior to use, and the results are measured against internationally recognized standard reference materials from a trusted pharmaceutical reference standards supplier.

This ensures the results' reliability, allowing consumers and laboratories worldwide to trust and replicate the findings.

Standards are generally used for these types of analytical studies:

  • Assay,
  • Identification tests,
  • Analytical method validation,
  • Limit tests for related substances and more.

It is essential to understand the subtle distinctions between the types of standards used in chemical analysis.

These standards are typically classified into two main categories:

  • Primary standards or certified reference materials
  • Secondary standards or working standards

Primary Standard

A primary standard reference material from trusted impurity reference standards suppliers is an ultra-high purity compound used in analysis involving assay, identification or purity tests. It may consist of a single compound or a mixture containing the analyte of interest in a defined and certified concentration.

Any impurities present must be identified and carefully controlled before the material is used in assay studies. The chosen primary standard should exhibit high stability, be free from moisture or hydration, and be traceable to a recognized national or international standards organization.

In many instances, obtaining reference material from those sources may not be feasible due to the following reasons:

  • A primary reference material for in-house use can be sourced from a specific production batch within manufacturing industries, often provided by a chemical reference standards supplier. After assigning a batch number, its characteristic properties are thoroughly documented for future reference and used as a benchmark for comparison with subsequent production lots.
  • The new molecule is encountered in R&D activity. In such cases where a reference standard is not available from official standard bodies, laboratories can rely on a reference compound with well-established purity for routine use.

Secondary or Working Standard

Primary standards are accompanied by a certificate of analysis and are traceable to internationally recognized standards bodies. However, they can be costly, even in milligram quantities.

This is where secondary or working standards become valuable. These high-purity materials are calibrated against primary standards and are commonly used for routine analyses in laboratories.

These working standards are assigned a limited validity period based on the material’s stability. Fresh working standards must be prepared before the existing ones expire. It is crucial to understand that using an expired working standard in analysis renders the reported results unreliable and lacking credibility.

Conclusion

Understanding the distinction between primary and secondary reference standards is essential for ensuring chemical analysis accuracy, consistency, and regulatory compliance. While primary standards offer certified precision and global traceability, secondary standards provide a cost-effective and practical alternative for routine lab use.