Applied Analytical Systems

Laboratory Reagents and Chemical Grades Selection Guide

Almost every laboratory uses chemicals and reagents in one form or another. Knowing where to buy them, what grade to purchase, and what labeling is required can be confusing. This guide will help you navigate some of those challenges:

Chemical Grades

Most laboratory chemicals are labelled with a grade which generally indicates the purity of the chemical. There are many different standards used in grading, however, the three you are most likely to encounter are: ACS, Reagent Grade and Laboratory Grade. Varying terminology is often used by different chemical manufacturers but as a general rule of thumb, ACS and Reagent Grades are usually the purest with Laboratory Grade being less pure. Since ACS Grade chemicals are supported by a batch specific Certificate of Analysis, these tend to be higher priced than the lower grades. Laboratory Grade chemicals are often used in less critical analyses and educational labs as a middle tier quality.

  1. ACS Grade
  • Alternate Names: American Chemical Society
  • Purity Level: Very High purity, ACS means that the chemical or reagent purity meets or exceeds the standard set out by the American Chemical Society.
  • Applications: Suitable for use in many laboratory and analytical applications
  1. Reagent Grade (R/G)
  • Alternate Names: Analytical Reagent (AR), Guaranteed Reagent (GR), UNIVAR, AnalaR, Premium Reagent (PR)
  • Purity Level: Very high purity, meets the standards set by American Chemical Society (ACS). Usually includes batch specific Certificates of Analysis. The Assay is usually printed on the label.
  • Applications: Can be used in all scientific areas where quality is critical. Quantitative analysis in QA environments. Research laboratories. Producing primary standards (buffers, volumetric solutions)
  1. Laboratory Grade (L/G)
  • Alternate Names: Laboratory Reagent (LR), UNILAB, Chemically Pure (CP)
  • Purity Level: Relatively high purity, exact levels of impurity unknown. Often meets BP, USP or FG standards – certification needs to be checked if suitable for use in these applications. Product specifications generally available.
  • Applications: Excellent for teaching and educational labs, not pure enough for food, drug or medicinal use. Often used for general lab work where an analytical reagent is not required.
  1. Technical Grade
  • Alternate Names: Tech Grade (TG), Commercial Grade
  • Purity Level: Contains impurities. Basic product specifications usually available. Sometimes complies with Food Grade certification.
  • Applications: Used in low grade applications and/or qualitative testing. Often supplied in bulk for industrial or commercial applications.
  1. Other Grades

These grades are application specific, extensive data is available from key manufacturers and distributors.

  • HPLC grades- This grade includes solvents, ion pair reagents and buffers of appropriate purity to be used as mobile phases in HPLC. The solvents undergo highly efficient distillation, solid phase absorption and other chemical treatments. This allows eliminate of impurities that could interfere in HPLC analysis.
    • AAS/ICP Standards – spectroscopic grade reagents pure enough for use in spectroscopy instruments such as AAS and ICP.
    • Molecular Biology grade – Pure enough for use in molecular biology and biochemical applications.

References

www.wikipedia.com

www.westlab.com

Posted by Oluwakemi Adi

[email protected], 08060874724

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