SPE is a popular sample pre-treatment enabling purification and concentration of target analytes(1). A wide range of currently available SPE sorbents ensures various selectivity and are available in various formats including column cartridges, discs and well-plates and pipette tips, sometimes called disposable pipette tip extraction(3) (branded as Dispersive Pipette Extraction). Dispersive Pipette Extraction has been cited in numerous journal articles as a reliable option for performing solid phase extraction(4). Conventional SPE cartridges are used with a vacuum or positive-pressure manifold. These formats suffer from flow rate control issues resulting in columns drying out and/or inefficiencies like channeling and low recoveries (3).
INTip SPE utilizes a patented device that is unique from all other SPE devices because sorbent material is loosely contained between two barriers within a pipette tip. The design allows a sample solution to aspirate into the pipette tip and mix with the sorbent. The disperser helps to perturb the sample solution and loose sorbent during multiple aspirate and dispense steps. Every sorbent particle actually faces analyte several times. Mixing during aspiration and dispense steps provide enhanced interaction between the sorbent and analyte providing optimal binding efficiencies. This is contrary to conventional SPE, where a greater amount of sorbent is needed because the analyte comes into contact with the sorbent particles only once(5). This process is not dependent on sample flow-rate(6) and the highly efficient interaction of the sorbent and sample solution results in fast extraction times, ideal analyte recoveries and minimized matrix effects.
DPX Technologies sources commercially available chemistry in a range of phases to provide selectivity for a diverse spectrum of analytes. XTR tips are manufactured to order per custom specifications. Tips can hold 1 – 100 mg of sorbent depending on the format. Method development can be done with a 1 mL Universal style tip that fits most handheld pipettes with no additional hardware like vacuum or positive pressure manifolds required. DPX Technologies also offers a 1 mL Pneumatic Extractor which can process 24 – 96 samples at one time. This allows even small labs to increase sample throughput to save time and costs.