Sorbent for solid phase extraction

Varian has introduced PLEXA, a sorbent for solid phase extraction (SPE) that is suitable for extraction of bioactive compounds from natural sources and biological fluids.

The sorbent was created by Varian and Polymer Laboratories and uses a new kind of SPE, termed 'pore-exclusion SPE'.

Pore-exclusion is suitable for isolating small pharmacologically active compounds in biological fluids such as animal or human plasma or urine, and in natural products such as fermentation broths or worked up samples of plant or marine organisms.

Each PLEXA particle incorporates a hydrophilic exterior and a hydrophobic interior that is inaccessible to proteins and other macromolecules and which repels inorganic salts. The result is a sorbent that offers high absolute recovery for target molecules, using one of two simple methods.

Furthermore, the exclusion of inorganics, heavily ionised molecules like phospholipids and macromolecules, from the hydrophobic internal surface means the extract gives reduced ion suppression in the LC-MS. Lower ion suppression translates into better linearity and sensitivity, making it suitable for GLP applications.