Molecular recognition mechanism based stationary phase for trace analysis

For numerous application fields, the challenge relies on the necessity to detect compounds at the trace level (often sub µg/L). This last decade, the sensitivity of the analytical method based on the coupling of separation methods with mass spectrometry has been largely improved. However, complex samples still require an efficient pretreatment step in order to remove sample components that can interfere in the determination of target analytes (co-elution in the chromatogram, presence of isobaric compounds and matrix effects during ionization in mass spectrometry). The pretreatment step consists in the extraction and the concentration of the target analytes while removing other matrix components.

Solid-phase extraction (SPE) is a method of choice because of the availability of a large choice of sorbents present under various formats (cartridges, precolumns, pipet tips…). However, in the search of target compounds at trace and/or ultra-trace level, many conventional sorbents can lead to co-extraction of interfering compounds.
This can be circumvented by developing and then applying selective SPE sorbents that involve a molecular recognition mechanism, thus allowing the extraction of a target analyte or of a group of structural analogs.

• Immunosorbents : sorbent based on the use of immobilized antibodies
• Molecularly imprinted polymers (MIP) that are produced by radical polymerization or sol-gel approach using a template molecule to create specific cavities
• Oligosorbents : sorbent based on the use of immobilized aptamers, i.e. oligonucleotides sequence (ADN or ARN single strand) selected for their specificity toward (a) target analyte(s)