A guide to Chemical Grades

  • Reagent A.C.S. – This designates a high quality chemical for laboratory use. The abbreviation “A.C.S.,” means the chemical meets the specifications of the American Chemical Society. A Certificate of Analysis is available upon request.
  • Guaranteed Reagent (GR) – Suitable for use in analytical chemistry, products meet or exceed American Chemical Society (ACS) requirements where applicable. (EMD trademark)
  • AR – The standard Mallinckrodt grade of analytical reagents; suitable for laboratory and general use. If the reagent also meets the requirements of the American Chemical Society Committee on Analytical Reagent, it will be denoted as an AR (ACS) reagent. (MBI trademark)
  • Primary Standard – Analytical reagent of exceptional purity that is specially manufactured for standardizing volumetric solutions and preparing reference standards.
  • Reagent – The highest quality commercially available for this chemical. The American Chemical Society has not officially set any specifications for this material.
  • OR – Organic reagents that are suitable for research applications.(MBI trademark)
  • Purified – Defines chemicals of good quality where there are no official standards. This grade is usually limited to inorganic chemicals.
  • Practical – Defines chemicals of good quality where there are no official standards. Suitable for use in general applications. Practical grade organic chemicals may contain small amounts of isomers of intermediates.
  • Lab Grade – A line of solvents suitable for histology methods and general laboratory applications.
  • USP – Chemicals manufactured under current Good Manufacturing Practices and which meet the requirements of the US Pharmacopeia.
  • USP/GenAR – A line of chemicals manufactured under cGMP, meet the requirements of the 1995 USP 23, meet European Pharmacopeia (PhEur, EP) and British Pharmacopeia (BP) specifications where designated, and are Endotoxin (LAL) tested where appropriate. (MBI trademark)
  • NF – Chemicals that meet the requirements of the National Formulary.
  • FCC – Products that meet the requirements of the Food Chemical Codex.
  • CP (Chemically Pure) – Products of purity suitable for use in general applications.
  • Technical – A grade suitable for general industrial use.


  • OmniTrace Grade Acids – Higher purity than Reagent Grade, suitable for trace metals analysis. Acids are analyzed for a minimum of 33 different metals. Trace metals are typically in the ppb range. (EMD trademark)
  • Tracemetal – Acids manufactured to achieve very low metal contamination in ppb range. Primarily used in digestion of samples prior to ICP analysis. Each lot is analyzed for 32 metals by ICP/MS. (Tedia designation)
  • Tracemetal Plus – For critical trace metal analyses, the acids are manufactured by double sub-boiling distillation to achieve low metal contamination in ppt range. Each lot is analzed for 32 metals by ICP/MS. (Tedia designation)
  • Suprapur Grade Acids – High purity grade acid produced by E. Merck. Suitable for sensitive instrumental methods. Trace metals in low ppb range, frequently less than detection limits. This grade applies to acids and salts. (EMD trademark)
  • AR Select – A line of acids specifically developed for trace metal analysis; analyzed for up to 28 metals in the 0.05 to 0.0005 ppm range. (MBI trademark)
  • AR Select Plus – The purest grade of Mallinckrodt acids. AR Select Plus acids are manufactured utilizing sub-boiling point, quartz-lined stills and are packaged in fluoropolymer bottles to maintain purity. These products are tested for 45 elements in the 3.5 to 0.005 ppb range, ensuring low background interference. (MBI trademark)
  • Environmental Grade – Extremely high purity acids refined through a single sub-boiling distillation process. (Anachemia trademark)
  • Environmental Grade Plus – Acids produced by distilling Environmental Grade acids a second time. This product is double sub-boiling distilled acid and is of the highest purity available. (Anachemia trademark)

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