What are chemical grades?Chemical grades are a way of quantifying the purity of a particular chemical. There are several different standards set by various organizations, such as the American Chemical Society and the United States Pharmacopeia.
What are the different grades of chemicals?There are many different grades currently in use. Some are standardized, like ACS and USP, while others (like lab or technical grade) are slightly more subjective and not as common. Here, we’ll cover some of the most commonly used grades. ACS: Sometimes interchangeable with reagent or GR grade, this grade meets or exceeds the purity standards set by the American Chemical Society (≥ 95% purity). This grade is acceptable for food, drug, or medicinal use, but is more expensive than lesser grades due to the high purity requirement. USP: USP grade chemicals meet or exceed the standards set by the United States Pharmacopeia, the organization that sets the bar for chemicals that can be used in pharmaceutical products. USP grade is therefore equivalent to pharmaceutical grade. NF grade: This is a standard set by the National Formulary (NF). The National Formulary and the United States Pharmacopeia co-publish a joint compendium of purity standards every year, known as the USP-NF. They are typically comparable to USP grade in terms of purity, although it’s best to check the yearly compendium if more specific information is needed. HPLC: HPLC is an acronym for High Performance Liquid Chromatography, a versatile analysis technique that requires high-quality materials to provide reliable results. HPLC grade chemicals are specifically manufactured for HPLC. They typically have a purity of over 99.9% and a low viscosity. Food grade: Food grade is a little tricker. They can signify that a chemical additive is safe for consumption when added to food (like citric acid and sodium benzoate). They can also signify that a chemical is safe to use around food, for cleaning kitchen spaces and cookware, and ingesting trace amounts won’t be harmful (like food grade ethanol). Laboratory grade: Lab grade chemicals are not as pure as reagent grade chemicals (but still relatively pure) and their exact level of impurity is unknown. They’re very popular for educational laboratory purposes, but are not suitable for food, drug, or medicinal use. They are also classified as LR grade. Technical grade: Technical grade chemicals are high enough quality for industrial use, but not for food, drug, or medicinal use. They’re typically used in large scale commercial manufacturing.
What is AR/OR?AR grade is the “standard Macron Fine Chemicals™ grade of analytical reagents; suitable for laboratory and general use”, and OR grade signifies organic reagents suitable for research applications. These are good examples of trademarked grades. A lot of companies make their own designations for chemical purity, like VWR’s Macron Fine Chemicals™ grades (AR, AR Select, ChromAR, etc.) and Sigma Aldrich’s BioXtra and BioReagent grades. The easiest way to find out about these sorts of specific grades is to use the company’s own guideline to them. Most companies have some sort of chart or table available: for example, you can find Sigma Aldrich’s grades here and Fisher Scientific’s here.
What is a reagent? How many types of reagents are there?A reagent is a substance that causes a chemical reaction. Reagents are typically divided into organic (those which contain carbon-hydrogen bonds) and inorganic (those which do not), although there are other categories based on your intended field of use. For example, in organic chemistry reagents are typically classified as nucleophiles and electrophiles.
What is the most acceptable chemical grade?There is no universally acceptable chemical grade. As you have seen, there are dozens of different categories, each with their own specifications and uses. When deciding which is best for you, you should take your exact situation into consideration. Do you need a very high purity chemical, or is lower okay? What kind of budget are you working with? How readily available are chemicals in your area? These are all questions to consider when picking a chemical grade to use.
What do some of LabAlley’s chemical grades mean?LabAlley has a few exclusive grades. Extraction grade means the chemical is suitable as a solvent for medicinal plant, herbal, and botanical extraction processes. Gradient grade means that the chemical is suitable for use in HPLC with gradient analysis.
What are some recommended grades for household and industrial use?Lab grade, technical grade, or even ungraded chemicals are less expensive than high purity grades like ACS and USP, and are therefore more suitable for general purposes. These grades are often bought in 1-gallon bottles, 5-gallon pails, 55-gallon drums, 250 and 270-gallon totes, and pallet sizes. We have provided the most widely accepted definitions of chemical grading terminology, but they are not universal. To see how other companies and organizations may categorize these grades, check out these examples:
|ACS||Meets or exceeds standards set by the American Chemical Society.||Food, drug, medicinal use; any application requiring stringent quality specifications|
|USP||Meets or exceeds standards set by the United States Pharmacopeia.||Pharmaceutical manufacturing, personal care, medical and first aid|
|NF||Meets or exceeds standards set by the National Formulary||Pharmaceuticals, medical purposes|
|HPLC||High-purity with physical properties suitable for high performance liquid chromatography.||High performance liquid chromatography|
|Food||Safe to use in or around food.||For use in food or to clean surfaces and cookware that will be used with food|
|Laboratory||Relatively high purity, but exact percentage and nature of impurities is unknown.||Educational laboratories|
|Technical||Have a level of impurity making them unsuitable for high-purity applications but fine for industrial use.||Industrial use, commercial manufacturing|
|Extraction grade||Suitable as a solvent for medicinal plant, herbal, and botanical extraction processes.||Medicinal plant, herbal, botanical extraction processes|
|Gradient grade||Suitable for use in HPLC with gradient analysis.||HPLC with gradient analysis|