What Do The Different Grades Of Chemical Mean?

There are many different types of chemical grades, which determine where and how a chemical product can be used. Generally speaking, the different grades of chemicals refer to how pure and free from contaminants they are. While each country, lab and organisation have their own ways of classifying chemical products, they are usually based on similar principles and regulations. 

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What Are The Different Chemical Grades?

Classifying chemicals based on purity and quality is essential to determine which type of chemical to use for a particular purpose, such as laboratory experiments or industrial processes. In the UK, we have our own set of standards for different grades of chemicals. Other countries may have similar standards, but there will be some variations. Each company may also have slightly different specifications.

Here are some of the most common chemical grades in the UK for general chemical products:

  • Technical Grade: This is the lowest grade of chemical in terms of purity level and quality. The chemical products that belong in this category are intended for industrial applications, where the high purity of chemical reagents and precursors is not completely essential, as long as the intended reactions occur.
  • GRG: General Reagent Grade, or General Grade chemicals, are those that are suitable for laboratory use and household purposes. Chemicals under this category have a high purity level of up to 99.9%. However, no specific standard test is conducted to determine if there are contaminants in GRG mixtures. 
  • BP Grade: Otherwise known as pharmaceutical grade chemicals, this category is very similar to the American USP Grade. BP Grade chemical products conform to the standards established by the British Pharmacopoeia, which are based on the level of purity and lack of contaminants in a substance. Chemical products that are able to comply with these standards are given a certificate of analysis or conformity. Since BP grade chemicals are commonly used in manufacturing cosmetic products, this certification is necessary in order to prove that a product has undergone the required testing and verification.
  • Analytical Research Grade: Chemical products under this category are considered very high quality, and are designed for specialist analytical laboratory testing. The high degree of purity of the products is necessary for accurate and precise testing. This is because if a product contained contaminants in this setting, it could skew the results of the test. 
A scientist analysing a beaker in a lab
Analytical Research Grade chemicals are high-quality and used for specialist analytical laboratory testing

Specific categories of chemicals also have their own separate classifications. For instance, in the United States, acids have grading levels that are based on purity and intended use. These are some of the common classifications of acid grades:

  • Omni-trace grade acids: Acids under this category have higher purity than reagent grade acids. Omni-trace grade acids are excellent for analysing the presence of at least 33 different types of metals in trace amounts, with a parts per billion range.
  • Trace metal grade: Acids that are manufactured under this grade have a very low level of metal contamination. Trace metal grade acids are used in inductively coupled plasma mass spectrometry (ICP-MS) tests to prepare samples.
  • Supra pure grade acids: Acids under this category are suitable for use with analytical instruments. Trace metal contents in these acids are so low that they can hardly be detected. The grade also applies to the salts produced by the acid reactions.
  • Environmental grade: Acids with this grade level are highly pure. This is because they undergo a single sub-boiling distillation process to remove impurities.

What Are Analytical Grade Chemicals?

Various industry-leading chemical companies have their own definitions of chemical grades based on government regulations. Therefore, there can be some very specific differences between classifications. Something that most companies in various countries agree on, however, is that analytical grade chemicals are the highest graded products in terms of purity and lack of contaminants. 

The high quality of analytical grade chemicals make them ideal for laboratory analytical purposes. They are used for testing other chemicals, including biochemical products such as enzymes and hormones. 

Analytical grade chemicals are also used for calibrating laboratory instruments. For example, they are used in the following processes to compare the sample value with the standard value:

  • Capillary electrophoresis
  • Chromatography
  • Electrochemistry
  • Microbiology
  • Spectroscopy
  • Titration

High levels of precision and accuracy of measurements in laboratory analyses are possible because of analytical grade chemicals. In turn, these measurements serve as the basis for creating new materials that can be manufactured into more high quality products.

What Are Lab Grade Chemicals?

Compared to analytical grade chemicals and reagent chemicals, lab grade chemicals are less pure. However, while their levels of impurities are usually not specified, they don’t contain excessive amounts of contaminants. Instead, their quality is considered to be upper-intermediate. 

Lab grade chemicals are typically used for educational purposes in school chemistry labs for a wide range of experiments, such as titration. This is because school-based experiments are intended as a demonstration of concepts, not for carrying out ultra-precise sample analysis. The important thing is that students are able to learn chemistry principles and methodologies, and lab grade chemicals are ideal for this. 

A school student carrying out a science experiment
Lab Grade chemicals are typically used for educational purposes in school chemistry labs

What Are Food Grade Chemicals?

Food grade chemicals are food ingredients that are compliant with health and safety regulations and international standards, such as the Food Chemicals Codex (FCC). These chemicals are manufactured in bulk and sold either in large wholesale containers or in retail packs.

Food grade chemicals refer to non-organic or organic chemical additives that are added to food in order to make it last longer, taste better, and look better, among other reasons. These chemicals are processed and mass produced by companies either for use by food companies, or for direct household use. Some examples of food grade chemicals are:

  • Antioxidants
  • Food preservatives
  • Artificial food colouring
  • Artificial flavouring
  • Vitamins and minerals

These chemicals are added to processed foods to extend their shelf lives and provide a wide range of flavourings. Certain types of processed foods are also fortified with vitamins and other micronutrients. Some food grade chemicals, like citric acid and baking soda, are also commonly used in households for baking and cooking. 

What Are GPR Grade Chemicals?

GPR grade chemicals are referred to in several ways, including guaranteed pure reagent grade chemicals, and also general pure reagent chemicals. These are laboratory grade chemicals that can have a purity rating of up to 99.9%. 

However, these products do not undergo strict testing for contaminants. This makes them suited for general laboratory use only, again as in school chemistry experiments, or testing for chemical reactions.

As reagents, GPR grade chemicals can also be used to maintain the quality of certain products. For example, reagents are efficient at testing for the presence of contaminants. They are also used to test the level of chemical reactions in a large batch of products, like beer and other manufactured beverages.

What Is Reagent Grade Water?

Reagent grade water is usually distilled water intended for specific laboratory testing procedures. When used as a reagent, it is important that water does not significantly interfere with the procedure or chemical reactions being tested. 

Ideally, it should contain as few contaminants as possible. This includes impurities like dissolved minerals, which can react with other chemicals in a solution and affect test results. In titration procedures, for example, pure water is necessary to gain accurate calculations of the molarity of the acid and base substances.

Reagent grade water has three general levels of classifications, depending on purity:

  • Type 1: This classification is necessary for critical laboratory applications, like DNA sequencing. The water reagent is prepared by distillation, deionisation, and filtration.
  • Type 2: General analytical laboratory procedures require this classification of reagent grade water. It is crucial that it is free from organic chemicals in these settings, where it is used for buffers, pH solutions, and microbial preparations.
  • Type 3: This is the lowest laboratory water grade recommended for rinsing laboratory glassware, heating baths, and filling autoclaves.
Amber vitamin pills on a yellow surface
Food Grade chemicals include things like vitamins, minerals, additives, and preservatives

What Does USP Grade Mean?

USP grade means United States Pharmacopeia grade. USP is a non-profit scientific convention whose standards are accepted in more than 140 countries. The USP standards are mainly focussed on food, drugs, and medical-grade chemicals.

In the United States, USP does not have the power to legally enforce its standards. The U.S. Food and Drug Administration (FDA) and other related government agencies are the ones responsible for the enforcement of laws and regulations.

The different grades of chemicals ensure that quality standards and product safety are followed. These grades serve as guidelines about the appropriate quality of chemicals that should be used.

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The blog on chemicals.co.uk and everything published on it is provided as an information resource only. The blog, its authors and affiliates accept no responsibility for any accident, injury or damage caused in part or directly from following the information provided on this website. We do not recommend using any chemical without first consulting the Material Safety Data Sheet which can be obtained from the manufacturer and following the safety advice and precautions on the product label. If you are in any doubt about health and safety issues please consult the Health & Safety Executive (HSE).