As an indispensable presence in laboratory reagents, what are the uses of acetonitrile? What benefits can acetonitrile bring to chromatographic analysis? Compared with methanol, what are its advantages? What personal protection should be paid attention to in use?
Acetonitrile (CH3CN) is a widely used organic chemical raw material. In addition to being used as an extractant for extracting butadiene and isoprene from olefins and alkanes in the petrochemical industry, it is also widely used as a synthetic raw material for fine chemicals such as organic synthesis, medicine, pesticides, surfactants, dyes, and as a mobile phase solvent for thin layer chromatography, paper chromatography, spectroscopy, polarography, and high performance liquid chromatography (HPLC), Recently, it has been used as a solvent for DNA synthesis/purification, a solvent for organic EL material synthesis, and a cleaning solvent for electronic components. These applications have high requirements for the purity of acetonitrile.
Analysis of the use of acetonitrile in the laboratory
1. Acetonitrile is a common polar aprotic solvent. Acetonitrile is widely used as a ligand in inorganic chemistry, which is called MeCN for short. For example, the acetonitrile complex PdCl2 (MeCN) 2 can be prepared by heating the suspension of polymerized palladium chloride in acetonitrile. Acetonitrile is a popular cyclic voltammetric solvent due to its high dielectric constant.
2. Acetonitrile is also a carbon dioxide raw material for organic synthesis. It reacts with cyanogen chloride to obtain malonditrile.
3. Acetonitrile is also used as a mobile phase separation molecule 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 synthesizing FDG, the evaporation of acetonitrile 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 drug quality; At the same time, acetonitrile is also used as the solvent and the matrix of the reaction system.
5. In addition, acetonitrile water mixture (e.g. 85% v/v) is also used as the mobile phase for thin layer chromatographic analysis in the 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 the analysis of high performance liquid chromatography (HPLC), the purity and quality of mobile phase solvent have an important impact on the analysis results and the instrument itself.
Various trace impurities in the solvent will not only cause high baseline and ghost peak, which will affect the qualitative and quantitative analysis results, but also may pollute the separation column and block the system, causing 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 application.
In the analysis of high performance liquid chromatography (HPLC), the purity and quality of mobile phase solvent have an important impact on the analysis results and the instrument itself.
Various trace impurities in the solvent will not only cause high baseline and ghost peak, which will affect the qualitative and quantitative analysis results, but also may pollute the separation column and block the system, causing 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 application.
The most commonly used organic mobile phase components
Acetonitrile is distinguished from other HPLC solvents by its unique properties (medium elution capacity, strong solubility, clear chromatographic peak, low viscosity, and low UV absorption compared with alcohols and esters), making it the most commonly used organic mobile phase component. Acetonitrile is generally a by-product of the large-scale production of acrylonitrile (from ammonia and propylene). It may contain a variety of very small impurities (such as acrylonitrile α ( β)- Methacrylonitrile, cis/trans butyronitrile, acetaldehyde, acetone, methanol, ethyl cyanide, acrolein, allyl alcohol, acrylic acid, oxazole and acetic acid).
After a complex purification process, trace amounts of the above impurities may still exist in HPLC acetonitrile. Some of the impurities will not only cause high baseline and ghost peak, which will affect the qualitative and quantitative analysis, but also pollute the analysis column and block the system, leading to instrument failure.
Determination of UV absorption value of acetonitrile in HPLC
The UV absorption background is critical to HPLC acetonitrile for two reasons. First, most organic impurities will generate UV absorption. The smaller the UV absorption of acetonitrile, the less impurities in it. Secondly, the most commonly used detection mode of HPLC instrument is UV detection. Therefore, the smaller the UV absorption of acetonitrile, the lower the baseline background of chromatography; The higher the sensitivity, the lower the detection limit.
Post time: Sep-14-2022