What are reagent agents || reagents in organic chemistry reactions

What are reagent agents || reagents in organic chemistry reactions

Reagent Agents (reagent), also known as biochemical reagents or reagents. It is mainly pure chemicals used in chemical reactions, analytical tests, research experiments, teaching experiments, and chemical formulas. 

Generally divided into general reagents, high-purity reagents, analytical reagents, instrumental analysis reagents, clinical diagnostic reagents, biochemical reagents, inorganic ion developer reagents, etc.

Classification of Reagents

Inorganic analysis reagent

Inorganic analytical reagents are commonly used inorganic chemicals for chemical analysis. Its purity is higher than that of industrial products with fewer impurities.

Organic analysis reagent

Organic reagents for inorganic analysis are special organic compounds such as precipitants, extractants, chelating agents, and indicators for the determination, separation, and enrichment of elements in the analysis of inorganic substances, not general ones. Solvents, organic acids and organic bases.


These organic reagents must have good sensitivity and selectivity. With the development of analytical chemistry and chemical industry, such reagents with better sensitivity and selectivity will be developed, such as those that have complex ability to some metals (such as alkali metals, alkaline earth metals) and ammonium ions that have appeared since 1967. This is the case for Crown ethers.

Reference reagent

Primary standards are compounds with high purity, few impurities, good stability, and constant chemical composition. Among the standard reagents, there are classifications such as volume analysis, pH measurement, and calorific value measurement. 

There is a distinction between primary benchmarks and working benchmarks in each category. All the first benchmarks must be verified by the National Academy of Metrology, and the production unit uses the first benchmark as the measurement standard for the work benchmark product. 

The standard reagents for commercial operations mainly refer to the capacity analysis work standards in the capacity analysis category [content range: 99.96% ~ 100.05% (weight titration)]. Generally used for calibration of titrants.

Standard material

Standard substances are chemicals used for comparison in chemical analysis, instrument analysis, or chemicals used to calibrate instruments. It’s chemical composition, content, physical and chemical properties, and impurities must be known and meet the regulations or be recognized. 

Micro-analytical reagents Micro-analytical reagents are reagents suitable for micro-analyses where the permitted amount of the substance to be determined is only one percent (weight of about 1-15 mg and a volume of about 0.01-2 ml).

Analytical standards

Organic analytical standards

Organic analytical standards are chemical reagents used for comparison when determining the composition and structure of organic compounds. Its composition must be precisely known. It can also be used for microanalysis.

Pesticide analysis standards

Pesticide analytical standards (Pesticide analytical standards) are suitable for comparison purposes when analyzing pesticides or determining pesticide residues by gas chromatography. Its content requires accuracy. There are solutions prepared from a small amount of a single pesticide, or mixed solutions prepared from multiple pesticides.

Atomic Absorption Spectroscopy Standards

Atomic absorption spectroscopy Standards (Atomic absorption spectroscopy standards) is in the use of atomic absorption spectroscopy analysis of a sample used as a standard reagent.

Refractive index liquid

Refractive index liquid is a high-purity stable liquid whose refractive index is known. It is used to determine the refractive index of crystalline substances and minerals. The refractive index of each package is marked on the outside.

Equivalent solution

The normal solution is an aqueous solution containing one gram equivalent of solute in one liter of solution, which means a solution with a concentration of 1N. 

Indicators are substances that can change their color due to the presence of certain substances. It is mainly used to indicate the end of titration in volume analysis. 

Generally, it can be divided into the acid-base indicator, redox indicator, adsorption indicator, and so on. In addition to analysis, indicators can also be used to test the presence of certain harmful and toxic substances in gases or solutions.

Instrumental analysis reagent

Instrumental analytical reagents are reagents used in the process of sample analysis using special instruments designed according to the principles of physics, chemistry, or physical chemistry.

For chromatography

For chromatography, reagents refer to reagents and materials used in analytical methods such as gas chromatography, liquid chromatography, gas-liquid chromatography, thin-layer chromatography, and column chromatography, and include fixed solutions, supports, and solvents.

For electron microscope

For electron microscopy reagents are reagents for fixatives, embedding agents, stains, etc. used in research work using electron microscopes in the fields of biology and medicine.

For polarography

For polarography (For polarography) reagent refers to the reagents required for quantitative and qualitative analysis by polarography.

Spectral purity

Spectral purity (Spectrography) reagent usually refers to the reagent with higher purity analyzed by emission spectroscopy.


Spectrophotometric pure reagent refers to the solution used in the spectrophotometric method, which has a certain wavelength transmittance for qualitative and quantitative analysis.

Biochemical reagent

Biochemical reagent refers to biological materials or organic compounds related to life science research, as well as reagents for clinical diagnosis and medical research. Due to the wide range and rapid development of life sciences, this kind of reagent has a wide variety and complex properties.

Other national standard reagents

National standard reagents: This class of reagents are stipulated by China’s national standards and are suitable for inspection, identification, and detection reagent grade (RG, red label): standard chemicals as reagents.

Teaching reagents: A class of reagents that can meet the teaching purpose of students without causing deviations in chemical reaction phenomena.

Designated grade (ZD), this kind of reagent is a chemical reagent customized for a specific user according to the quality control indicators required by the user.

High-purity reagents (EP): including ultra-pure, ultra-pure, high-purity, and spectral-pure, prepared standard solutions. 

The quality of such reagents is focused on the impurity content that may cause analysis results in the analysis of a particular method and interfere with component analysis or content analysis but does not place high requirements on the main content.

Indicator (ID): for the preparation of the indicator solution. The quality indicators are the discoloration range and the discoloration sensitivity. It can replace CP, but also suitable for organic synthesis.

Biochemical reagent (BR): Prepare biochemical test solution and biochemical synthesis. Quality indicators focus on biologically active impurities. Alternative indicator for organic synthesis

Biological staining agent (BS): Prepare staining solution for microbial specimens. Quality indicators focus on biologically active impurities. Alternative indicator for organic synthesis

Electronic purity (MOS): suitable for the production of electronic products, the content of electrical impurities is extremely low.

Electroplating grade: suitable for the production of the electroplating industry, less harmful impurities to the electroplating, purity is higher than an industrial-grade, slightly lower than chemical purity. Equivalent reagents (3N, 4N, 5N): The main component content is 99.9%, 99.99%, or 99.999% or more.

Electrophoresis reagent: The quality index focuses on the control of the content of electrical impurities.

In addition, there are special reagents with a very small production volume, which is almost on-demand production. The quantity and quality of such reagents are generally specified by users. 

Synthetic reagents: The so-called synthetic reagents are a class of chemical reagents that strictly provide the product with various physical constants on the premise of indicating the main content of the component.

Usual Format

Four Common Specifications

There are four commonly used specifications: excellent pure or first grade (GR, precision analysis and scientific research work), analytical pure or second grade (AR, important analysis and general research work), chemical pure or third-grade product (CP, Chemical experiments in industry, mining and schools), experimental reagents (LP).

Excellent grade (GR, green label): The main component content is very high and the purity is high, which is suitable for accurate analysis and research work, and some can be used as a reference substance.

Analytical purity (AR, red label): High content of main components, high purity, low interference impurities, suitable for industrial analysis and chemical experiments.

Chemical purity (CP, blue label): High content of main components, high purity, interfering impurities, suitable for chemical experiments and synthetic preparation.

Experimental pure (LR, yellow label): High content of main ingredients, poor purity, no choice of impurity content, only suitable for general chemical experiments and synthetic preparation.

The reference reagent content should be 99.9% to 100%. With the development of science and technology and emerging industries, the requirements for the purity, clarity and precision of chemical reagents have become more stringent and specialized.

It is widely used in analytical chemistry. The grade and specifications of the reagents should be selected according to specific requirements and use conditions. 

The classification is based on the purity (ie content) of the reagent, the content of impurities, the ease of purification, and various physical properties. Sometimes graded according to the application, such as spectrally pure reagents, chromatographically pure reagents, and pH standard reagents. 

Sanjay Bhandari

Hello Friends, My name is Sanjay Bhandari. I am a chemistry Teacher.

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