Dispersive magnetic solid-phase microextraction employing microfluidic platform: application to multiplexed determinations of antibiotics, aflatoxins and the diagnosis Mastitis in milk

Abstract

Determinations of analytes at low concentrations and/or in complex matrices usually require separation/concentration steps, and classical Solid Phase Extraction (SPE) has been generally exploited to this end. Development of novel magnetic materials, e.g., nano- and microparticles (NPs and µPs), led to the improvement of magnetic dispersive D-SPE. The sorbent is dispersed into the sample, interacts with the analyte(s), and is further recovered by means of a magnet. Due to the easy material modification, practically of use and low cost, the process has been mostly exploited for cleanup, derivatization and extraction. Applications of magnetic D-SPE in flow analysis are however scarce, and usually carried out under batch-wise conditions. Analytical flow systems may associate automation, low effluent generation, process versatility, and hyphention with the detection technique. Implementation of the approach usually involves NPs packed in the analytical path, which may lead to clogging and overpressure effects, as well as to the establishment of preferential pathways. These procedures are analogous to those exploiting ion-exchange resin columns, thus they do not take full advantage of the magnetic NPs potential. A novel strategy for accomplishing in-line D-SPE involving magnetic NPs is then proposed. The flow system, fully automatic, will comprise a module of electromagnets for handling the magnetic NPs. As applications (proof of concept), the methodology will be applied to the multiplexed determination of aflatoxin M1, antibiotics (sulfonamides and tetracyclines), and diagnosis of Mastitis in milk. (AU)