Acetonitrile with 0.1% ammonium acetate (CAS 148642-19-7)

Acetonitrile with 0.1% ammonium acetate is a specialized solvent mixture used extensively in analytical chemistry, particularly in liquid chromatography-mass spectrometry (LC-MS) applications. Acetonitrile, a polar aprotic solvent with the chemical formula CH3CN, is favored for its excellent solvation properties and low viscosity, which enhance the efficiency of liquid chromatographic separations. The addition of 0.1% ammonium acetate, a salt formed from ammonia and acetic acid, modifies the ionic strength of the solvent and acts as a buffering agent. This addition helps to maintain a consistent pH in the mobile phase, which is crucial for achieving reproducible chromatographic performance and improving the stability of sensitive analytes. The mechanism through which this solvent mixture operates involves the modulation of the elution strength and ionization efficiency during LC-MS analyses. Ammonium acetate in the mixture serves to enhance the ionization of analytes in the mass spectrometer′s source, a critical step for generating detectable ions in mass spectrometric analyses. This is particularly beneficial for the analysis of polar compounds, which might otherwise be challenging to ionize. The use of acetonitrile with ammonium acetate is particularly prevalent in the quantification and identification of small molecules and biomolecules in complex mixtures, offering a balance of good elution capabilities and compatibility with MS detection. This makes the solvent mixture a staple in pharmaceutical, environmental, and biochemical research, where precise and accurate mass spectral data are essential.