Solid phase extraction (SPE) is a widely used, proven method for sample preparation and sample clean-up in the field of forensic analysis. Most SPE products, however, are designed in such a way that relatively large volumes of solvent are required for the process. Consequencently, sample processing times, cost per sample, as well as limits of detection are often unnecessarily high, negatively affecting overall method performance and cost.
Disposable Pipette Extraction (DPX) was developed as an alternative to traditional SPE, combining efficient and rapid extraction with signifi cantly reduced solvent consumption. DPX is a novel dispersive solid-phase extraction technique that is based on sorbent loosely contained in a pipette tip in which it is efficiently mixed with sample solution. The main advantages of DPX technology are: rapid extractions, high recoveries, negligible solvent waste, and the fact that extractions can be fully automated and combined with direct introduction of the extracts to the chromatography system.
This study focuses on the automated extraction of small sample volumes combined with LC-MS/MS analysis providing high throughput analysis of common pain management drugs. Using a GERSTEL MultiPurpose Sampler (MPS), DPX extractions of hydrolyzed urine were performed, using a reversed phase sorbent with a proprietary salt additive (DPX-RP-S). The resulting eluents from the automated DPX extractions were introduced into an Agilent 6460 LC-MS/MS instrument.
Coupling DPX to LC-MS/MS provides rapid, just-in-time sample preparation for high throughput analysis. The DPX extraction removes potential matrix interferences, minimizing ion suppression and sample dilution and thereby achieving high overall sensitivity for the target analytes.
