Chemical Grades Explained
Organizations such as the American Chemical Society (ACS) and the American Society of the International Association for Testing and Materials (ASTM) set chemical grades that define the purity of a chemical. In a lab or an industry setting, understanding chemical grades is imperative to ensure the use of the appropriate grade and corresponding purity.
The guide below explains the terminology used by laboratory professionals and the chemical industry. Common terms and definitions of industry acronyms and abbreviations and the different chemical grades by their molecular makeup and application, for example, acids, standard solutions, and chromatography or spectrophotometry, are also included. This resource provides an efficient way to find the appropriate chemicals and chemical grades needed. Use it as your go-to guide for purchasing precisely what you need, and contact our knowledgeable customer service for support!
Chemical Grade Definitions from Highest to Lowest Purity
1. ACS
A chemical grade of highest purity and meets or exceeds purity standards set by American Chemical Society. Reagents meeting the requirements of the American Chemical Society Committee on Analytical Reagents. The specifications listed in this catalog are based on the ACS Reagent Chemicals Tenth Edition.
2. Reagent
High purity is generally equal to A.C.S. grade and suitable for use in many laboratory and analytical applications.
3. U.S.P.
A chemical grade of sufficient purity to meet or exceed requirements of the U.S. Pharmacopeia (USP); acceptable for food, drug, or medicinal use; may be used for most laboratory purposes. Chemicals manufactured under current Good Manufacturing Practices (cGMP) and which meet the requirements of the US Pharmacopeia.
4. NF
A grade of sufficient purity to meet or exceed requirements of the National Formulary (NF). Chemicals manufactured under current Good Manufacturing Practices (cGMP) and meeting the requirements of the National Formulary.
5. Lab
A line of solvents suitable for histology methods and general laboratory applications. A chemical grade of relatively high quality with exact levels of impurities unknown; usually pure enough for educational applications. Not pure enough to be offered for food, drug, or medicinal use of any kind.
6. Purified
Also called pure or practical grade, and indicates good quality chemicals meeting no official standard; can be used in most cases for educational applications. Not pure enough to be offered for food, drug, or medicinal use of any kind. Chemicals of good quality where there are no official standards or compendia, or in some cases, that meet the requirements of former compendia articles. Chemicals of good quality where there are no current compendia. Most purified chemicals were formerly listed in the USP and NF compendium. The specifications from the former compendia listing have been retained wherever possible.
7. Technical
The good quality chemical grade used for commercial and industrial purposes. Not pure enough to be offered for food, drug, or medicinal use of any kind. A grade suitable for general industrial use.
Pharmacopeia (USP), National Formulary(NF), and Food Chemicals Codex (FCC) are chemicals that conform to the requirements of the United States Pharmacopeia (USP), the National Formulary (NF), and the Food Chemicals Codex (FCC). These products are regulated by the Food and Drug Administration. All meet the requirements necessary for their use in pharmaceutical processing and prescription compounding (USP and NF) and for use in food processing operations (FCC).
Grades of Chemicals
General Chemicals
| Chemical Grade | |
|---|---|
| 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) Suitable for use in analytical chemistry, products meet or exceed American Chemical Society (ACS) requirements where applicable. Grade applies to both solid and liquid chemicals. |
| 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 | Products of a purity suitable for use in general applications. Chemicals of sufficiently high quality for use in diverse applications. Some products may contain intermediates, isomers, or homologs. 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. Selected economical grade of commercial purity, less than reagent grade. |
Acids
| Chemical Grade | |
|---|---|
| OmniTrace™ Grade Acids | Higher purity than Reagent Grade. PPB purity. Suitable for trace-metal analysis. Packaged in poly coated glass bottles. Actual lot analysis on the label. 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. E ach 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) |
High Pressure Liquid Chromotagraphy & Spectrophotometry
| Chemical Grade | |
|---|---|
| OmniSolv HPLC Grade Solvents | Reagent quality products tested for suitability in High Performance Liquid hromatography. Products meet ACS requirements for use in HPLC and Ultraviolet spectrophotometry. (EMD trademark) |
| HPLC/Spectro | High purified organic solvents, acids, salts, ion-pair reagents and mobile phases. Specifically tested for UV transmittance at multiple wavelengths. For standard chromatography requirements in HPLC and spectrophotometry procedures.(Tedia designation) |
| ChromAR | Solvents that meet ACS specifications and are suitable for liquid chromatography and UV-spectrophotometry. (MBI trademark) |
| SpectrAR | A line of solvents designed for UV-Spectrophotometric applications. (MBI trademark) |
Multiple Application Solvents
| Chemical Grade | |
|---|---|
| OmniSolv Grade Solvents | High purity solvents. Manufactured using state-of-the-art purification equipment. Tested for suitability in HPLC including gradient analysis, Spectrophotometry, Residue Analysis and Gas and Liquid Chromatography as listed in the individual monographs in the catalog. Specially purified products tested for environmental analysis (example: Methanol for Purge and Trap). Actual lot analysis on label. EMD brand of high purity solvents. Manufactured using state-of-the-art purification equipment. Tested for suitability for Spectrophotometry, Residue Analysis, Gas and Liquid Chromatography as listed in catalog. |
| Absolv | Specially distilled to purity levels exceeding the requirements for HPLC, TLC, GC, and pesticide residue analysis. (Tedia trademark) |
| UltimAR | Solvents that meet ACS specifications and provide consistent performance for liquid chromatography, extraction/concentration, UVSpectrophotometry and general purpose use. (MBI trademark) |
| Accusolv | Distilled in glass solvents for Liquid and Gas Chromatography, Residue Analysis and Spectrophotometry. (Anachemia trademark) |
Pesticide & Residue
| Chemical Grade | |
|---|---|
| HR-GC OmniSolv Grade Solvents | EMD brand of highest purity solvents available. Tested for suitability for High Resolution Gas Chromatography. Actual lot analysis on label. Capillary GC-FID & ECD chromatograms of 1000:1 concentrate provided on each bottle. Highest purity solvents available. Tested for suitability for High Resolution Gas Chromatography. Capillary GC impurities at parts per trillion levels by ECD / parts per billion level by FID. Actual lot analysis on label. |
| Nanograde | Solvents that meet ACS specifications for organic extraction/concentration procedures that utilize ECD and FID detection methods. (MBI trademark) |
| Residue Grade Sovents | Solvents tested for suitability in Pesticide Residue Analysis. |
Standard Solutions
| Chemical Grade | |
|---|---|
| Standardized Solutions | Solutions are prepared with raw materials which meet or exceed requirements of the American Chemical Society. Where no A.C.S. specifications exist, chemicals of highest purity available are used. All aqueous solutions are prepared using high purity, deionized, water which meets requirements for ASTM type 1 Reagent Grade water. These solutions are standardized direct to NIST standards or primary standard grade materials where available. (Specific to Reagents manufactured solutions) |
| StandARd | Prepared solutions including titrants and atomic absorption standards. These solutions are suitable for use in ACS, USP and NF compendia methods and general laboratory applications. (MBI trademark) |
| Acculute | Standard volumetric solutions concentrates packaged in spacesaving ampoules or sealed poly bottles. (Anachemia trademark) |
Bio Tech Applications
| Chemical Grade | |
|---|---|
| OmniSolv Biosynthesis | EMD brand of high purity biotechnology solvents. Tested for suitability for biomolecular synthesis, sequencing andchromatographic separations under gradient and isocratic conditions. Solvents are amine-free, 99.9+% purity, low water content and low acidity. (EMD trademark) |
| GenAR | A line of reagents specifically developed for use in biotechnology and genetic research. |
| Accugen | High purity glass distilled or recrystallized reagents for biotechnology and molecular biology. |
| BIO | Solvents specially purified and analysed for biotechnology applications. |
| Anhydrosolv | Solvents specially dried to meet a water specification of less than 50 ppm. These high purity solvents are packaged in septum-seal bottle. |
| DriSolv | Solvent specially dried for Organic Synthesis. Septum-Sealed bottles. Water content as low as >10ppm. Specifically designed for organic synthesis. Available in 100ml and 1L bottles and EM ReCycler® containers from 20L to 1,250L. |
Miscellaneous
| Chemical Grade | |
|---|---|
| ScintillAR | Chemicals specially controlled for use in liquid scintillometry. |
| SilicAR | Silica gel products with physical and chemical characteristics that are optimal for column and thin layer chromatography. |
| Accutint | pH test Paper in an easy-to-use dispenser. |
| OmniTrace Ultra™ Grade Acids | Highest purity grade available. PPT purity. Test by ICP/MS after concentration. Packaged in pre-cleaned PTFE bottles. CoA's report results for more than 60 elements and ions. |
| OmniSolv® Biosynthesis Solvents | High purity biotechnology solvents. Tested for suitability for biomolecular synthesis, sequencing and chromatographic separations under gradient and isocratic conditions. Solvents are amine-free, 99.9+% purity, low water content and low acidity. Actual lot analysis on label. |
| OmniPur® Molecular Biology Grade Reagents | Suitable for use in biological applications. Materials procured and handled to minimize potential of biological contamination. Where possible and applicable, tested to be free from RNase, DNase and Protease contamination. Where possible and applicable, tested to be free from other biological contamination or absorbance interferences. |
| Suprapur® Grade | High purity acids, salts and solutions. PPB trace-metal purities. Suitable for most instrumental analyses. Acids are packaged in borosilicate glass bottles; salts in poly bottles. |