µSPE clean-up of QuEChERS extracts

Technology

The QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction is commonly used for the analysis of pesticides and other contaminants in a variety of matrices. It usually involves extraction with acetonitrile in the presence of a mixture of salts followed by centrifugation. An aliquot of the supernatant is then cleaned-up by a manual dispersive-solid-phase extraction (d-SPE) in an attempt to remove unwanted matrix compounds.

The μSPE clean-up uses a cartridge (depicted on the right) replacing dSPE. It empowers reliable, high-throughput sample processing with minimized labor input and instrument maintenance. The μSPE clean-up of QuEChERS extracts is undertaken in a scavenging mode, where unwanted matrix is retained by the µSPE sorbent, and contaminants are recovered in a sharp elution profile.

Watch a video explaining the workflow of the µSPE QuEChERS extract clean-up

Technology

New PAL System μSPE cartridges

Micro-SPE has developed as the new standard for extraction, clean-up, concentration, or filtration for automated green analytical workflows. The design of the new PAL System µSPE cartridge allows for the reliable automated processing with high sample throughput, accomplishing the principles of green sample preparation.

The new PAL System µSPE cartridge consists of two parts. The polymer material used is chemically inert and free from leachables. The outer part (1) provides a higher capacity and flexible volume for filter disks (3) and the sorbent material (4). The bottom outlet is designed to penetrate pre-slit septa and to deliver directly to LC injection ports. The inner plunger (2) provides critical functionality with the compression of the sorbent/filter layers, and a precise needle guide for safe and upright transport. An essential feature is the ability to withstand high pressure and prevent leakage around the syringe needle, which allows for faster loading of larger sample volumes. Applications range from food pesticides, water, and drug analysis to forensic and pharmacological applications.

The recent publication by Nicolas Michlig and Steven J. Lehotay (US Department of Agriculture, Wyndmore PA, USA) evaluated the novel septumless µSPE cartridge with high extract load flow rates in the range of up to 10 µL/s, using extract volumes of up 600 µL. More than 250 pesticides were tested using the QuEChERSER methodology with LPGC-MS/MS analysis, which achieved recoveries of 80 to 120% for more than 260 pesticides. Optimization experiments led to a routine extract load volume of 500 µL at 5 µL/s flow rate.