## 3 MIPs' Applications
### MIPs in Separation Techniques
For the first time a MISPE protocol was developed for the selective extraction of four different 5-nitroimidazoles and three of their metabolites in egg powder. The 5-nitroimidazoles and their deuterated analogues showed similar and good behavior on the MISPE cartridges with satisfactory linearity at the concentration studied. The validated method provided enough accuracy, reproducibility and sensitivity. In the real matrice, the lack of real internal standard was observed for two analytes while the others gave recovery higher than 91%. Several studies applying imprinting technology to different selective extraction techniques have appeared over the last few years such as Solid-Phase Microextraction (SPME), Stir-Bar Sportive Extraction (SBSE) and Matrix Solid Phase Dispersion (MSPD) techniques. The first work on SPME appeared in 1990 [121] and, since then, many different studies have looked at using this simple method to extract different analytes from many different matrices. Firstly the fibers were synthesized and then MIPs were used as sorbents on those fibers by using a bulk polymerization method. In this case, the monolith obtained from traditional polymerization is attached to a solid support. A suitable silylation of the support is important for this technique, but there is no standardization so far on the fibers preparation step and there are several different supports described in literature to attach the fibers. The most widely-used support has been a commercial fiber in which the coating surface has been etched away [122, 123]. For instance, [PERSON] _et al_. extracted ascorbic acid from human serum with recoveries of 100% without any sample pretreatment. Another way to obtain SPME fibers is, by using a glass capillary, filling it with the polymerization mixture and inducing the polymerization process inside [124, 125]. Another support that can be used is a hollow tube, such as an optic fiber, to which the MIP is attached [126]. A common limit for most of these fibers is their fragility since they are formed by highly cross-linked monolithic polymer. MIPs have been used as coating agents also for Stir-Bar Sportive Extraction (SBSE) technique [127, 128, 129] first introduced by [PERSON] _et al._ in 1999 [130] with the main purpose of increasing the mass of sorbent used in SPME fibers. This technique is based on the use of a magnet covered of polydimethylsiloxane which is able to retain some compounds present in solution. Desorption of the extracted compounds is performed using very low volumes of organic solvent or thermally in gas chromatography equipment. For instance, [PERSON] _et al._[129] selectively extracted four estrogens from water samples. They used an iron bar held inside a glass tube and sililated the outer surface of the glass. Then the glass was put inside a mixture of polydimethylsiloxane, \(\beta\)-cyclodextrinrin as the template molecule and all the typical compounds involved in the synthesis of a normal stir-barand a molecularly imprinted polymerization. This step was repeated several times until the desired thickness of the stir-bar was achieved. Matrix Solid-Phase Dispersion (MSPD), commonly used for solid samples, is another extraction technique which differs from the previous ones mainly since the extraction can also be performed directly on solid, semisolid and viscous samples. In this technique the sample of interest and the sorbent are blended together; then, the obtained mixture is packed into an empty column or a SPE cartridge or a syringe. Finally, the analytes can be extracted through two different ways depending on their affinity towards the sorbent used. When there is a high retention of the analyte of interest on the sorbent, a solvent can be added into the cartridge to remove the interfering compounds; while if the analyte of interest is not strongly retained on the sorbent, a solvent able to disrupt only the weaker interactions can be added to directly remove the analyte. In MSPD extraction method, any commercially available sorbent can be used.