Porous Polymer Monolith Microextraction Platform for Online GC-MS Applications

Abstract

One of the key steps in chemical analysis is sample preparation. It is a very important step prior to analysis, otherwise the analyte signal could be suppressed by sample matrix interference. In most cases sample preparation entails some form of extraction of the analyte(s) of interest from the interfering species. Conventional extraction techniques include liquid-liquid extraction (LLE) and solid phase extraction (SPE). LLE involves mixing two immiscible solvent together, and based on solubility equilibria the analyte or the interfering species partitions preferentially in the organic solvent. Ideally, the partition coefficient is very high to allow for efficient extraction (Park et al., 2001). In SPE, analytes of interest are extracted from solution by passing the liquid through a solid phase, such as a C18 SPE cartridge. Based on different physical and chemical properties, the desired solute either is adsorbed onto the solid phase, from whence it can later be eluted, or remains in solution while impurities are retained on the solid phase (Korner et al., 2000). The LLE and SPE extraction methods are laborious and demand the use of copious amounts of samples and solvents, therefore driving up the cost of chemical analysis. For LLE, emulsion formation can be a nuisance. These methods are also limited by factors like cartridge clogging in SPE, single use of the SPE and the need for toxic and polluting solvents (such as halogenated solvents like chloroform and dichloromethane) in LLE.