What is acetonitrile usage and function?

Acetonitrile is an indispensable laboratory reagent. What are its uses? What benefits can acetonitrile bring to chromatographic analysis? What are the advantages over methanol? What personal protection should be paid attention to in use?

Acetonitrile (CH3CN) is an organic chemical raw material with a wide range of uses. In addition to being used as an extractant for extracting butadiene and isoprene from alkenes and alkanes in the petrochemical industry, it is also widely used as a synthetic raw material of fine chemicals such as organic synthesis, medicine, pesticides, surfactants and dyes. As well as thin layer chromatography, paper chromatography, spectroscopy, polarography and high performance liquid chromatography (HPLC) mobile phase solvents, recently began to be used as DNA synthesis/purification solvent, organic EL material synthesis solvent, electronic components cleaning solvent, etc., these uses have high requirements for the purity of acetonitrile.

Acetonitrile is of great use in the laboratory：

1. Acetonitrile is a common polar aprotic solvent. Acetonitrile is widely used as a ligand in inorganic chemistry, and its abbreviation is MeCN. For example, the acetonitrile complex PdCl2(MeCN)2 can be prepared by heating the polymerization of palladium chloride suspension in acetonitrile. Acetonitrile is a popular cyclic voltammetry solvent due to its high dielectric constant.

2. Acetonitrile is also a two-carbon raw material for organic synthesis. It can be reacted with cyanide to obtain malonitrile.

3. Acetonitrile is also used as a mobile phase separation molecule and is commonly used in column chromatography and more modern high performance liquid chromatography.

4. In the field of nuclear medicine, acetonitrile is used to synthesize positron radioactive drugs such as fluorodeoxyglucose. In the process of FDG synthesis, acetonitrile evaporation can take away the water in the reaction system; The amount of acetonitrile in the reaction system has a decisive influence on the synthesis efficiency of FDG and the quality of the drug. Acetonitrile is also used as solvent and substrate for the reaction system.

5. In addition, a mixture of acetonitrile and water (e.g. 85% V/V) is used as the mobile phase for TLC analysis in routine quality inspection of FDG.

Application of chromatographic acetonitrile:

Chromatographic acetonitrile refers to acetonitrile reagent used for chromatographic analysis, chromatographic separation and chromatographic preparation

In high performance liquid chromatography (HPLC) analysis, the purity and quality of mobile phase solvent have an important influence on the analysis results and the instrument itself.

The various trace impurities in the solvent not only cause high baselines and ghost peaks, which affect the qualitative and quantitative analysis results, but also may contaminate the separation column and clog the system, resulting in instrument failure.

Understanding HPLC solvent specifications and related test methods can help HPLC users evaluate and screen HPLC solvents and reduce the negative impact of solvent impurities on applications.

In high performance liquid chromatography (HPLC) analysis, the purity and quality of mobile phase solvent have an important influence on the analysis results and the instrument itself.

The various trace impurities in the solvent not only cause high baselines and ghost peaks, which affect the qualitative and quantitative analysis results, but also may contaminate the separation column and clog the system, resulting in instrument failure.

Understanding HPLC solvent specifications and related test methods can help HPLC users evaluate and screen HPLC solvents and reduce the negative impact of solvent impurities on applications.

The most commonly used organic mobile phase components

Acetonitrile is the most commonly used organic mobile phase component due to its unique properties (medium elution, strong solubility, ability to obtain well-defined chromatographic peaks, low viscosity, and low UV absorption relative to alcohols and esters) that distinguish it from other HPLC solvents. Acetonitrile is generally a byproduct of mass production of acrylonitrile (from ammonia and propylene). It may contain a variety of impurities in very small amounts (e.g., acrylonitrile, α(β) -methylacrylonitrile, cis/trans butenonitrile, acetaldehyde, acetone, methanol, ethyl cyanide, acrolein, allyl alcohol, acrylic acid, oxazoles, and acetic acid).

After a complex purification process, trace amounts of these impurities may still be present in HPLC grade acetonitrile. Some of these impurities not only cause high baselines and ghost-peaks, which affect qualitative and quantitative analysis, but also contaminate analytical columns and clog systems, leading to instrument failures.

Determination of UV absorption value of acetonitrile by HPLC

UV absorption background is critical to HPLC acetonitrile for two reasons. First, most organic impurities produce UV absorption. Less UV absorption of acetonitrile means less impurities. Second, UV detection is the most commonly used detection mode for HPLC instruments. Therefore, the lower the UV absorption of acetonitrile, the lower the baseline background of chromatography; Therefore, the higher the sensitivity, the lower the detection limit.