Titre : Precision Sample Preparation with Molecularly Imprinted Polymer Microextraction Devices for Targeted Mass Spectrometric Analysis of Biological and Environmental Samples
Heure : 11h00
Campus MIL, Local : A-3541
Résumé :
Coupling microextraction devices coated with porous polymer sorbents to either benchtop or hand-held mass spectrometers presents a unique opportunity to streamline small molecule screening protocols for biological and environmental samples. Although approaches like dilute-and-shoot are easy, they suffer from matrix effects on response linearity and lead to instrument contamination. Polymer-based solid phase microextraction is widely used for sample clean-up, is compatible with small sample volumes, and can be easily scaled for high-throughput parallel sample processing. With a wide variety of functional monomers available, the coatings of porous organic covalent networks can be tailored for selectivity, porosity, surface area, and sample compatibility; such polymers can also be prepared as a coating on almost any substrate. In a process that has come to be known as molecular imprinting, a template molecule provides a scaffold (self-assembly prior to polymerization) for monomers that results in favourable orientation of functional groups at the binding sites, increasing binding affinity for target analytes and enhancing selectivity over other matrix components. Through careful control of the polymer composition, including amount and type of porogenic solvent, imprinting can be enhanced and polymer porosity tuned to balance the surface area needed for high extraction efficiency (microporous) against desirable mass-transfer dynamics (macroporous), the latter being of particular concern during direct MS interrogation where quick desorption is crucial. In this talk, our approaches to molecular imprinting will be presented along with the data from several materials we have developed for analysis of pharmaceuticals in blood and pesticides in aqueous samples. The adaptability of the coated blade format will be discussed, along with the utility of a coated mesh device for ultra-trace pesticide analysis. Data from UHPLC-MS/MS, direct introduction to MS (blade-spray), and a hand-held mass spectrometer (MX908) will be included.
