SPE cartridge

The strata-X Online SPE cartridge is designed for fast sample preparation. It uses strata-X, a reversed phase polymer SPE sorbent from Phenomenex. The sorbent is a polar functionalised styrene-divinylbenzene polymer that is capable of exhibiting hydrophobic, p-p, dipolar and hydrogen bonding retention mechanisms. The 25 µm particle has a surface area of >800 m2/g, resulting in an analyte capacity that is claimed to be higher than that of saliva-based sorbents. The strata-X sorbent is available in a 20 x 2 mm cartridge for convenient online processing.

Online SPE allows simulta-neous extraction, concentration, and separation for the rapid analysis of drugs in biological matrices. Using the cartridge detection limits of 100-200 picograms can be achieved. In addition, higher sample loads compared to offline SPE can be utilised without compromising cleanliness or linearity.

The online cartridge can be used either standalone (for less demanding separations) or in tandem with an analytical column, a choice not available with offline SPE.

Total sample clean-up and analysis can be accomplished in as little as 1.2 minutes when used in standalone fashion or 3 minutes when used in tandem with an analytical column. The direction injection of plasma samples eliminates the need for offline sample preparation (conventional SPE or protein precipitation). The online technique permits repeated injections (>200) of plasma samples, frequently in larger volumes compared to offline SPE.

The strata-X system is also available in 1, 3, 6 and 12 mL syringe barrel tubes and 96 well plate formats.