Liquid Chromatography Mass Spectrometry

Overview

Chromatography is the science of separations and is defined by the IUPAC (International Union of Pure and Applied Chemistry) as: A method used primarily for the separation of components of a sample, in which the components are distributed between two phases, one of which is stationary while the other moves. In gas chromatography the mobile phase is a gas and the technique involves the volatilization of the sample, usually by heating. Consequently the components of the sample must be thermally stable. Because of this requirement, only about 25% of all organic chemicals can be analyzed by the process. In liquid chromatography the mobile phase is a liquid. This method can be used for the analysis of samples which have low volatility, are polar, are not thermally stable or consist of large molecules.

Instrumentation

A JEOL LCmate instrument coupled with a Waters separation module has recently been purchased by Shrader and is equipped with two different types of sources for the analysis of a great variety of chemicals. ESI (electrospray ionization) is used for polar compounds and large molecules and APCI (atmospheric pressure chemical ionization), a soft ionization technique, for the analysis of relatively non-polar compounds. Both sources can be used in the positive or negative ion mode for even more applications.