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Introduction of General-purpose Solvents by Specification

Do you know that solvents like ethanol and acetone, which you often use, actually have more than 50 specification? In this article, we outline the specifications of reagents including general-purpose solvents and introduce general-purpose solvents upgraded for various purposes.

What Are the Specifications of Reagent?

Today's society is filled with different types of chemical substances (compounds). For example, there are more than 170 million CAS-registered chemical substances1) that support our rich lives in all situations. Among such chemical substances, the "chemical substances used for measurement criteria, detection/identification of substances, quantification, separation/purification, organic synthesis, physical property measurement, etc. in testing/research such as inspection, testing, research, experiment, etc., whose quality is assured according to the intended use and which are suitable for use in a small quantity"2) are called reagents.

Table 1 shows 4 categories of reagents (reagents for general use/reagents for specific use/reference materials and standard solutions/high-purity reagents) and intended use example.2-4)

Table 1. Classification of Reagents

Classification by intended use Intended use
For general use (Guaranteed Reagent/Wako Special Grade/Wako 1st Grade) Generally used without limiting the use. There are many JIS standards (example: Guaranteed Reagent) and in-house standards conforming to JIS (example: Wako Special Grade... Equivalent to JIS special class, Wako 1st Grade... Equivalent to old JIS class) for general-purpose products.
Specific use For instrumental analysis For instrumental analysis (for HPLC, for GC, for Atomic Absorption Spectrochemical Analysis, for ICP, for Spectrochemical Analysis, for Fluorometric Analysis, for Electron Microscopy, for NMR, for Spin Trapping)
For measurement of hazardous substances and environmental contaminants For measurement of hazardous substances and environmental contaminants (for Analysis of Poisonous Metals, for Pesticide Residue Analysis, for PCB Determination, for Oxidant Analysis, for Nitrogen Oxides Analysis)
For organic synthesis Reagents for organic synthesis (reagents used in discovery research of new compounds such as pesticides, drugs, polymers, and functional materials, research on their synthesis processes, or research on elucidation of the properties and functions of various organic compounds; starting materials for synthesis, intermediates, reactants, catalysts, solvents, separation/purification agents, etc.)
For biochemistry for Amino Acid Automated Analysis, for Amino Acid Sequence Analysis, for Fluorescent Labeling, for Electrophoresis, for Peptide Synthesis, for Immunochemistry (antigens, antibodies, for Immunocytochemistry, complements, adjuvants, and immunoassay-related reagents), for Genetic Research (gene recombination, for Nucleic Acid Synthesis, Gene Mutation Detection Kit), for Cellbiology, for Cell Culture [for animal tissue (cell) culture, for microbial culture, for vegetable tissue (cell) culture], Glycobiology.
For laboratory tests General-purpose reagents, reagent kits, and prepared reagents; Reference material, control serum, staining solution
Other pH standard solution, for Thin Layer Chromatography
Reference standards (analytical standards) and standard solutions Analytical standard for volumetric analysis, metal standard solution, ion standard solution, pH standard solution, analytical standard for environmental/food analysis
High-purity reagent High-purity reagents for advanced fields such as electronics and biotechnology

Due to the reagent characteristics of small amount and large variety, manufacturing is performed not by continuous mass production using dedicated production facilities as is the case with general chemical industries but by a small batch method using common facilities, and it is said that setting of reaction conditions to provide uniform quality is difficult3). Therefore, the quality of the reagent must be kept constant for stable and reproducible manufacturing and analysis using the reagent. In this way, the specification of the reagent ensures that the quality of the reagent is always maintained under a stable condition.

Type of Reagent Specification

There are different types of reagent specifications as shown below.

National/International Standards

Depending on which organization, establishes the specifications for reagents, there are 2 types of specifications: domestic specifications (U.S. ... ACS, Japan ...JIS, etc.) established by public organizations in each country and international specifications by the International Organization for Standardization (ISO).

[1] JIS standard

The typical Japanese standard is the Japanese industrial standard (JIS). This is a public specification set by the Council of the Ministry of Economy, Trade and Industry, "Japanese Industrial Standards Committee (JISC)"5) based on the Industrial Standardization Act, and as of February 2021, there have been a total of 10,899 specifications, of which 1,784 have been set by Division K (Chemical Engineering) regarding chemical substances. It includes specifications for individual chemical substances (including the scope, common items, types (special class), properties, quality, test methods, containers, storage methods, and labeling) and special chemical substances (JIS K 8008: biochemical reagents, JIS K 8007: highly purified reagents) in addition to specifications (KIS K 0050: general rules for chemical analysis, JIS K 8001: General rules for test methods of reagents) that specify chemical analysis methods, and reference materials for analysis. For example, 3 specifications have been established for acetone (JIS K 1503: 1st grade, JIS K 8034: special grade, JIS K 8040: for pesticide residue and PCB tests).

[2] Standards of various laws and regulations

In addition, it may be required to meet the standards of various laws and regulations such as the Law Concerning the Examination and Regulation of Manufacture, etc. of Chemical Substances, the Pharmaceuticals and Medical Devices Low, and the Poisonous and Deleterious Substances Control Low.

[3] In-house specifications

In addition, there are in-house specifications independently established by reagent manufacturers in each country (example. Wako Special Grade/Wako 1st Grade). Each manufacturer has established specifications for reagents with various quality assurance, including chemical substances not registered in the above standards of public institutions, etc.

Specifications of General-purpose Solvents

Next, let's look at the specifications of general-purpose solvents.

Table 2 summarizes the specification of FUJIFILM Wako reagents by intended use, the presence or absence of official specifications such as JIS and laws/regulations, and the presence or absence of corresponding specifications of representative general-purpose solvents (Methanol, Ethanol, Acetone, Acetonitrile, Tetrahydrofuran). Although there are as many as 34 specifications, it can be seen that only 7 specifications correspond to JIS standards, legal regulations, etc., and the other specifications are optimized for individual use.

Table 2. Classification of FUJIFILM Wako Reagents by Intended Use for Representative Solvents

For biochemistry

Classification by intended use Name of FUJIFILM Wako specification official specification General-purpose Solvent
Methanol Ethanol Acetone Acetonitrile Tetrahydrofuran
for general use Wako 1st Grade
Guaranteed Reagent
Wako Special Grade
Specific use for Instrumental Analysis for HPLC
for LC/MS
for GPC
for QTofMS
for the Japanese Pharmacopoeia General Tests (for Liquid Chromatography)
for Spectrochemical Analysis
for NMR
for Preparative Chromatography
Concentration 5000/300
for Measurement of Hazardous Substances and Environmental Contaminants for Boron Determination
for Dioxin Analysis
for Trihalomethane Analysis
for Tiuram Analysis
for PFOS-PFOA Analysis
for Aldehyde Analysis
for Environmental Analysis
for Vinyl Chloride Monomer Analysis
for RoHSⅡ
for Organic Synthesis for Organic Synthesis
for Nucleic Acid Synthesis
for Biochemistry Super Special Grade
for Proteomics
for Cell Culture
for Molecular Biology
for Drug Testing Japanese Pharmacopoeia
for Medicine Test
High-purity reagent Infinity Pure
for Electronics Industry
Other for Chromatography
for Determination of Wetting Tension

For Acetonitrile

As shown in Table 3, the specifications of acetonitrile of Guaranteed Reagent were compared with that of 3 specifications for instrumental analysis, including that for HPLC, for LC/MS, for QTofMS.

Table 3. Each Specification Value of Acetonitrile

Specification item Guaranteed Reagent for HPLC for LC/MS for QTofMS
Assay (capillary GC) (%) min. 99.5 min. 99.8 min. 99.8 min. 99.8
Density (20℃) (g/mL) 0.780 ~ 0.784 0.780 ~ 0.783 0.780 ~ 0.783 0.780 ~ 0.783
Refractive index nD20 1.343 ~ 1.346 1.343 ~ 1.346 1.343 ~ 1.346 1.343 ~ 1.346
Water (%) max. 0.1 max. 0.05 max. 0.05 max. 0.05
Residue after evaporation (ppm) max. 0.005 max. 0.001 max. 0.001 max. 0.001
Acidity (as CH3COOH) (ppm) max. 0.01 max. 0.001 max. 0.001 max. 0.001
Ammonium (NH4) (ppm) max. 0.3 max. 0.3 max. 0.3
Peroxides (as H2O2) (ppm) max. 5 max. 5 max. 5
Hydrogen cyanide to pass test
Substances reducing permanganate to pass test to pass test to pass test to pass test
Gradient test to pass test to pass test
(Suitability for QTofMS analysis: to pass test )
Particles (0.5 μm or more) (particles/mL) max. 100 max. 100
Absorbance 200 nm max. 0.05 max. 0.05 max. 0.05
210 nm max. 0.03 max. 0.03 max. 0.03
220 nm max. 0.02 max. 0.02 max. 0.02
230 nm max. 0.01 max. 0.01 max. 0.01
240 nm max. 0.005 max. 0.005 max. 0.005
Fluorescence test to pass test to pass test to pass test
Suitability for LC/MS analysis to pass test
Suitability for QTofMS analysis to pass test

There are 20 specifications of acetonitrile for each intended use, but in chromatographic analysis such as HPLC, it is used for mobile phase and dissolution of samples. The contents of these 3 specifications are higher than that of the Guaranteed Reagent by 99.8% or more, and impurities such as residual moisture and nonvolatile matter are reduced. In addition, special tests ensure appropriate performance for analysis, such as:

  • Absorbance/gradient test: Stability of background when detecting ultraviolet-visible absorbance, suppression of baseline variation
  • Fluorescence test: Reduction of background noise of fluorescence detector
  • Number of particles: Reduction of the effect on column life
  • Suitability for LC/MS analysis: Reduction of background noise of mass spectrometer
  • Suitability for QTofMS analysis: Connect the column to UHPLC, perform gradient measurement using QTofMS, and the baseline variation is not more than the standard. Quality control using multivariate analysis

The solvent is treated by the original technology to meet the performance suitable for each analysis, and the packaging form (removal of contamination from the cap, dedicated resin or aluminum cap, brown glass bottle with reduced elution, etc.) to minimize the contamination from the reagent container is adopted.

For Acetone

In Table 4, the specifications of acetone of Guaranteed Reagent were compared with that of 4 specifications, for Environmental Analysis, for Organic Synthesis, and for Electronics Industry. Acetone is frequently used for cleaning, but it has characteristics in the specification items depending on the intended use.

Table 4. Each specification value of acetone

Specification item Guaranteed Reagent for Environmental Analysis for Organic Synthesis for Electronics Industry
Assay (capillary GC) (%) min. 99.5 min. 99.8 min. 99.5 min. 99.7
Density (20℃) (g/mL) 0.789 ~ 0.792 0.789 ~ 0.792 0.789 ~ 0.792 0.789 ~ 0.792
Refractive index nD20 1.358 ~ 1.360 1.358 ~ 1.360 1.358 ~ 1.360
Water (%) max. 0.3 max. 0.3 max. 0.001 max. 0.25
Residue after evaporation (ppm) max. 5 max. 2 max. 5 max. 1
Acidity (as CH3COOH) (ppm) max. 20 max. 15 max. 10
Ammonium (NH4) (ppm) max. 10 max. 10 max. 1
Aldehydes (as HCHO) (ppm) max. 20 max. 20 max. 10
Methanol (CH3OH) (ppm) max. 500 max. 500 max. 500
Substances reducing permanganate max. 2 max. 2
Other special specifications Residual elements
Ag, As, Ba, Ca, Cd, Co, Li, Mg etc....max. 0.5 ppb
Fe, K, Sn etc....max. 1 ppb
  • for Environmental Analysis: Confirm that there are no endocrine disruptors and halogenated organic substances using high-resolution GC/MS or GC-ECD. Assure that the content is not less than 99.8% and the content of non-volatile matter is not more than 2 ppm.
  • for Organic Synthesis: Reduce the amount of water that inhibits the reaction to 0.001% or less.
  • for Electronics Industry: Impurities are removed to the limit for semiconductor industry. Assure that the content is not less than 99.7%, water content is not more than 0.25%, non-volatile matter is not more than 1 ppm, various elemental impurities are not more than ppb, particle control, etc.

Abbreviation

  • ACS=American Chemical Society
  • CAS=Chemical Abstracts Service
  • ESR=Electron Spin Resonance spectroscopy
  • GC=Gas Chromatography 
  • GC-ECD=Gas Chromatograph‐Electron Capture Detector 
  • UHPLC=Ultra High Performance Liquid Chromatography
  • HPLC=High Performance Liquid Chromatography
  • ISO=International Organization for Standardization
  • JIS=Japanese Industrial Standards 
  • JISC=Japanese Industrial Standards Committee
  • LC/MS=Liquid Chromatography - Mass Spectrometry
  • NMR=Nuclear Magnetic Resonance spectroscopy
  • PCB=PolyChlorinated Biphenyl 
  • PFOS=PerFluoroOctaneSulfonic acid, PFOA=PerFluoroOctanoic Acid
  • ppm=parts per million 1ppm = 0.0001%
  • ppb=parts-per-billion 1ppb = 0.001ppm = 0.0000001%
  • QTofMS=Quadrupole Time-of-flight Mass Spectrometer 

Reference

  1. American Chemical Society:CAS REGISTRY - The gold standard for chemical substance information
    http://www.cas.org/content/chemical-substances
  2. Japan Reagent Association web site
    https://www.j-shiyaku.or.jp/
  3. Nishiyama, S.: Chapter 4 Specifications of Reagents: Japan Standards Association Group, Development Teaching Materials for Standardized Education Program, Individual Technology Area Edition, Chemistry
    https://www.jsa.or.jp/datas/media/10000/md_2506.pdf
  4. National Institute of Advanced Industrial Science and Technology, Metrology and Standards Institute, Japan Reagent Association: Revised 4th edition, Guidebook for Reagents: The Chemical Daily (2020)
  5. Japanese Industrial Standards Committee web site
    https://www.jisc.go.jp/eng/index.html

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