Magnetic solid phase extraction coupled to ambient ionization mass spectrometry
Direct coupling of microextraction techniques and ambient ionization mass spectrometry opens a door to rapid, selective and sensitive analyses that are quite attractive in the bioanalytical field. The use of nanoparticles (NPs) in this combination may be problematic since they are not fully compatible with MS although they have a great potential as sorbent in microextraction techniques. In fact, these NPs may be blown during the ionization step causing the entering of this material in the spectrometer. Prof. Yu-Qi Feng and coworkers have recently proposed the use of magnetic NPs (MNPs) for this arrangement avoiding the previously mentioned shortcoming. The extraction protocol follows the typical workflow of a dispersive solid phase extraction (DSPE). In short, the MNPs are dispersed into the sample to favor the interaction/isolation of the analytes. Afterwards, they are cleaned-up with an appropriate solvent and finally recovered in a special capillary for instrumental analysis. T...