Chemical reagent definition

Chemical quality indicators

The quality of chemical reagents is complex and numerous, and it is particularly confusing. General conventional varieties (a type of reagents) are required varieties, there are 225 kinds, in China's Beijing, Tianjin, Shanghai, Xi'an, Chengdu, Guangzhou, Shenyang chemical reagent base is basically complementary production. Class II reagents are used in virtually all fields and are also essential for manufacturers. There are approximately 1,800 to 2,000 varieties. These types of reagents have a large demand and are widely used. There are about 3,000 to 6,000 varieties of the three types of reagents. Most of their use areas are related to the specific industrial reagents used in the national economy and people's livelihood such as chemical industry, metallurgy, electric power, food, medicine and health.

In China, there are 225 kinds of chemical reagents represented by three grades of pure grade, analytical grade and chemical grade according to the national standards of the People's Republic of China and the Ministry of Chemical Industry. These 225 chemical reagents form the basis of the standard, which stipulates the content of chemical reagents in our country. The determination of other chemicals is based on this standard and the content is determined by measurement. Therefore, the quality of these chemical reagents is very important. At the same time, these 225 chemical reagents have become basic varieties due to their extremely wide range of uses. These 225 varieties have been marked in the chemical reagent catalog. In addition, there are special reagents, production capacity is very small, almost on-demand production, the number of users is generally specified.

Premium grade (GR, green label): high content of main components, high purity, suitable for accurate analysis and research work, and some can be used as reference materials.

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

Chemically pure (CP, blue label): high content of main components, high purity, interference impurities, suitable for chemical experiments and synthetic preparation.

Experimental pure (LR, yellow label): The main component content is high, the purity is poor, the impurity content is not selected, and it is only suitable for general chemical experiments and synthetic preparation.

Indicators and Colorants (ID or SR, Violet Labels): Specific sensitivity is required.

Designated (ZD): Customized chemical reagents for specific users based on quality control specifications required by the user.

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

Equivalent reagents (3N, 4N, 5N): The main component content was 99.9%, 99.99%, and 99.999%, respectively.

In addition, it is still divided into the following more than 20 levels.

AAS Atomic Absorption Spectroscopy, BC Biochemical Reagent, BP British Pharmacopoeia, BR Biological Reagent, BS Biological Stain, CR Chemical Reagent, EP Special Purification, FCP Chromatography, FMP Microscope, FS Synthesis, GC Gas Chromatography, GR Priority Pure reagent, HPLC high pressure liquid chromatography, ID indicator, IR infrared absorption spectroscopy, MAR microanalysis reagents, NMR nuclear magnetic resonance spectroscopy, OAS organic analysis standards, PA analysis, Pract practice, PT reference reagents, Purisse purity, Purum Pure, SP Spectrum Pure, Tech Industrial, TLC Thin Layer Chromatography, UP Ultrapure, USP US Pharmacopoeia, UV-UV Spectrophotometric Pure, JX Teaching Reagents... MI Pharmaceutical Grade, I Industrial Grade, F Food Grade, M Makeup Grade, S Solid, L Liquid, E Fine, C Crude...

Obviously, the quality standards for these chemical reagents are generally divided into the above-mentioned several quality grades, far from meeting scientific research production requirements.

Chemical reagent validity period

Chemical reagents are affected by external factors such as temperature, light irradiation, air and moisture in the process of storage, transportation, and sale, and are prone to deliquescence, mycin, discoloration, polymerization, oxidation, volatilization, sublimation, and decomposition. Changes make it ineffective and unusable. Therefore, reasonable packaging, proper storage conditions, and transportation methods should be used to ensure that chemical reagents do not deteriorate during storage, transportation, and sales. Some special requirements for storage and transportation should be handled according to special requirements. Some chemical reagents have a certain shelf life and must be used with care.

The effective period of a chemical reagent varies greatly with the chemical nature of the chemical. Under normal circumstances, chemically stable substances have a longer shelf life and simple storage conditions. To initially determine the stability of a substance, follow the following principles:

Inorganic compounds can be used for a long period of time as long as they are properly kept and the packaging is intact. However, those substances that are easily oxidized and easily deliquesced can only be stored within a short period of time (1 to 5 years) under conditions of protection from light, shade, and dryness, depending on whether the packaging and storage conditions are in compliance.

Organic small molecular weight compounds are generally more volatile and have better sealing and can be stored for long periods of time. However, it is easy to oxidize, decompose under heat, easily polymerize, and photosensitivity substances, etc. It can only be stored within a short period of time (1 to 5 years) under conditions of protection from light, shade, and drying, depending on whether the packaging and storage conditions are in compliance with regulations.

Organic macromolecules, especially lipids, polysaccharides, proteins, enzymes, peptides, and other life materials, are easily affected by microorganisms, temperature, and light, and lose their activity or deterioration. Therefore, they must be refrigerated (frozen) and preserved. Also shorter.

Reference materials, reference materials, and high-purity substances should, in principle, be kept strictly in accordance with the preservation regulations to ensure that the packaging is intact and protected from the chemical environment, and the storage time should not be too long. In general, the reference substance must be used within the validity period.

The stability of most chemicals is still relatively good, and the specific conditions should be determined by the actual use requirements. If the analysis data is as a general understanding, or if the analysis results do not have specific accuracy requirements, such as general teaching experiments, general requirements can be set on the quality level of chemical reagents. However, the factory test data is used to guide production. The quality indicators of chemical reagents must not be vague. The chemical reagents used for general synthetic preparation are, in most cases, met with industrial-grade chemical reagents. However, the research and synthesis of certain specialty chemicals, in some cases, the quality requirements of raw materials are very strict and need to be strictly controlled.

In actual use, people are always accustomed to using the date of production to judge the effectiveness of chemical reagents. For example, in an institution of higher learning, it has been seen that warehouse managers have cleaned up all chemical reagents that have been in the factory for more than two years and are ready to be destroyed. The reason is that they have expired. Not to mention the huge waste of money, the unique destruction of chemical dangerous goods alone is enough to deter. What's more, commercial companies are not allowed to make acquisitions to prevent businesses from deceiving people. The situation is deplorable. Its situation is pathetic! Later, it was said that these large quantities of chemical agents were buried "deeply buried."

In short, the effectiveness of chemical reagents, we must first make basic judgments based on the physical and chemical properties of chemical reagents, and then observe the preservation of chemical reagents, and then make conclusions based on specific needs.

The rational classification of chemical reagents has been far from meeting the needs of scientific research and production due to the drafting of national standards, and it has seriously hindered the production of chemical reagents in China. Relying on the existing 227 national standards and industry standards, it is difficult to give a large number of chemical reagents a quality specification; we cannot give all chemicals to a national quality standard, even mentioning To the reagents, the first thing that people think of is analytical pure or chemical pure. Even when people buy, regardless of their use, non-analytical analysis does not buy. This is also a lot of varieties that do not have national standards at present, but somehow, unreasonably given the product a red AR label cheating reasons. It is also due to the fact that in actual use, many cases do not require true "analysis of pure", and unscrupulous manufacturers intentionally affixed industrial products to "analysis-pure" labels, confusing purity levels, although quality accidents do not occur in most cases. However, it seriously interferes with the production and use of the real “standard material, analytical purity”.

Furthermore, since there are a large number of conventional chemicals, only 225 varieties are classified as current pure, analytically pure or chemically pure, then what else is necessary?

At present, there is an increasing tendency in the world to indicate the grade and purity of chemical reagents according to the main content of the chemical, physical constants, and the like. It is generally believed that when the main content, boiling point, melting point, density, refractive index, and even UV, IR, and NMR spectra are known, the purity and application range of a substance can be completely determined. This is the main difference between the content of chemical reagent labels in China and the content of foreign chemical reagent labels.

In fact, the so-called chemical reagents are chemical reagents used in chemical experiments; that is, chemical reagents needed for chemical experiments. The division of chemical purity and grade can be determined according to the chemical quality standards and applicable scope.

According to this, chemical reagents are divided into four categories: standard reagents, biochemical reagents, electron reagents, and experimental reagents.

The classification principle of the Level 1 standard not only defines the quality standard, but also takes into account the scope of application of the chemical reagent.

The Level 2 standard is a further division on the basis of the Level 1 classification. It is a further definition and limitation of the Level 1 standard.

Level 3 standards are mainly for comparison with the original old standard, or indicate more precisely defined uses.

After the level 1 or level 2 is determined, the quality index of a chemical agent and the application purpose to which this quality index can be applied are determined.

Therefore, the author proposes to publish the quality standard of "standard reagent" which is the standard and scale of the analytical test to the explicit national standard. The quality indicators of other “biochemical reagents, electronic reagents, and experimental reagents” can be determined by the market according to the company's standards or the increasingly updated process requirements. In this way, our chemical reagent industry will be able to get out of the old “set dead” box and develop. Flourish!

Standard reagents BZ: In accordance with international norms and technical requirements, as a clear reference substance for the analysis of arbitration.

Biochemical reagents SH: formulated biochemical tests and biochemical synthesis.

Electronic reagents DZ: generally refers to the chemicals and materials used in the electronic information industry, including integrated circuits and discrete device chemicals, printed circuit board supporting chemicals, surface assembly chemicals, and display device chemicals.

Experimental reagent SY: "Synthetic reagent" determined according to "main content". Experimental reagents are used in chemical laboratories to synthesize, separate, and purify common reagents that meet the synthetic process requirements.

Chemical reagent label

The quality indicators of chemical reagents determine the applicable range of chemical reagents, so the author suggests that a national standard for “chemical reagent labeling” should be published, and a quality indicator specification for a chemical reagent specification should be given in the standard. It is of great significance to standardize production and rational use.

Chemical Reagent Labels carry information:

Registered Trademark: Clearly marks the trademark registered by the manufacturer.

Quality standards: Quality standards are displayed in both color and Chinese phonetic codes. The color display area is the manufacturer information area at the bottom of the label; the pinyin code (such as BZ, SH, DZ, SY) is marked in a prominent place.

Chinese name and type: The name of the product is based on the "Naming Principles of Inorganic Chemicals System" and "Systematic Naming Principles of Organic Chemicals" promulgated by the Chinese Chemical Society in 1982, taking into consideration the common names and trade names used for a long time. And as accurately as possible given the type or dosage form that can describe the chemical agent, for example: aqueous solution, alcohol solution, powder, block, stick, paste, and even particle size such as 200 mesh and so on.

English name: The product name is based on IUPAC's "Naming Principles for Inorganic Chemicals" and "Systematic Naming Principles for Organic Chemicals" published by IUPAC in 1982, taking into account the common names and trade names used for a long time.

The CAS registration number: consists of 9 digits in square brackets and is divided into three parts by a hyphen. For example, [58-08-2] is the CAS registration number of ***.

Molecular formula = molecular weight: The molecular formula is correctly written, that is, the molecular formula, and the molecular weight is accurately calculated according to the international atomic weight published in 1968. Such as NaOH = 40.10.

Main ingredient content: According to the molecular method stipulated by the national standard or enterprise standard, the mass percentage content of the chemical reagent is determined. Such as 99.9%.

Package amount: Solid material gives the mass packaged amount of the chemical agent, such as 1g, 5g, 10g, 25g, 100g, 250g, 500g, 1000g, and the like. A liquid or gas gives the volumetric packaging of the chemical, such as 1 ml, 5 ml, 10 ml, 25 ml, 100 ml, 250 ml, 500 ml, 1000 ml, and the like.

Appearance: Use succinct and accurate words to describe the physical state of the chemical reagent such as color, odor, and state of matter.

Physical constants: Physical constants such as "melting point, boiling point, density, viscosity, optical rotation, refractive index, and solubility" are given in this order.

Characteristic spectrum: Characteristic absorption peaks such as "ultraviolet, infrared, nuclear magnetic spectrum" are given.

Interference impurity content: gives the mass percentage of the main impurities, especially the accurate measurement value of the main interference impurities.

Dangerous goods rule number: The dangerous goods rule number must be marked. Production lot number: Give the production lot number for traceability.

Development characteristics of foreign chemical reagents

Developing to supporting, spare reagents and supporting services
Supporting benefits are due to improved service and user convenience. Currently, in foreign markets, almost all of the routine experiments and testing projects in industry, agriculture, health, environmental protection, scientific research, and teaching include test strips, supporting solutions, pre-packed columns, pre-coated sheets, and various reference standards. Special tools and handy small instruments. At present, foreign markets already have special supporting reagents for combinatorial chemistry, such as the basic modules of peptides: p-amino acids, Fmos (methyl methoxycarbonyl)-amino acids and other amino acid reagents; basic modules for organic synthesis: acid chloride, Alcohols, phenols, aldehydes, amines, carboxylic acids, ketones, etc.; as well as matching reagents according to user requirements. Most reagent companies, for the convenience of users, also sell small instruments, safety articles, various map data (chemical structures, infrared, ultraviolet, emission spectrum, chromatography, etc.), compound safety data materials, and various kinds of materials frequently used in laboratory work. Analysis of test method data, etc., a considerable part of which is published on the CD-Rom CD.
Many reagent companies not only sell tangible products, but also carry out technical consulting services to provide a wide range of technical services, such as: analysis and testing, intermediate product amplification test, product process design, drafting of environmental protection programs.
Pays great attention to scientific research and development
Each reagent company has its own research and development department, and most companies also cooperate with universities, research institutes, well-known scientist individuals or other companies to develop and even merge companies with certain technical expertise to enhance the company's development and competitiveness. They do not hesitate to invest heavily in scientific research and development in order to gain a dominant position in the sudden and explosive technological advancement and fierce market competition. Taking Merck KGaA as an example, the funds used for scientific research and development in 1994-1998 accounted for 9.56%, 9.O%, 8.18%, 9.76% and 10.05% of the sales revenue each year. In the same period, Merck (Darm. ): 43.52%, 43.94%, 45.29%, 47.0% and 46.95%.
Production, business management and process technology continue to improve
Most of the company's factories have obtained ISO 9001, ISO 9002, GMP or FDA quality management certification. The process, industrial hygiene, and environmental protection at the production site are generally highly valued. Over the past few years, as the variety of supply markets has continued to expand, many more complex process technologies have been widely adopted. The application of computer-aided production, technology, and management has become widespread. Most reagent companies have established their own websites on the Internet. In addition to reporting on the history of the company, its institutional structure, business scope, and catalogs, it is mainly online shopping, and it constantly releases (about weekly) the status of the company's operations. , technical achievements, foreign cooperation, planning guidelines and other information. Their annual fixed asset investment is huge. Take Merck KGaA as an example. From 1994 to 1998, the ratio of fixed asset investment to sales was 7.2%, 8.4%, 7.4%, 6.7%, and 7.7% respectively (eg: 1998 This is 624 million marks, equivalent to 2.8 billion yuan.)
Alliance, cooperation and joint management are trends
The categories of chemical reagents are extremely complicated, and they have a wide range of services. They cover almost all areas of economics and science and technology. It is impossible for any company to acquire all the reagents. The reagent sales feature is that the more types of products it sells, the more sales it increases. The greater the chance, the greater the possibility of profit. Therefore, 20 years ago, there was a tendency for small companies to move closer to large companies, large companies and small companies, or operate in conjunction with each other. At present, the largest supplier of Sigma-A1drich products in the world is the Sigma-A1drich company. Their advantages in variety are almost irreplaceable. This is indeed the result of joint operations.