## 5 MIP Applications for the Extraction of Antibiotics in Milk
### Amphenicols
MIP4 SPE-CAP cartridges (MIP Technologies, Lund, Sweden) were used for the development of a MISPE-liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) method for the determination of CAP in raw milk, skimmed milk and milk powder samples. The MIP4 SPE-CAP cartridge was preconditioned with methanol (1 mL) and water (1 mL), loaded with pre-treated spiked raw milk extract (1 g) and washed with water (2 mL), water-acetonitrile (95:5, \(v/v\); 1 mL) that contained 5% acetic acid, water (2 mL) and water-acetonitrile (80:20, \(v/v\); 1 mL) that contained 1% of a 25% ammonia solution. The cartridge was dried under vacuum for 10 min and washed with dichloromethane (3 mL). The analytes were eluted with water-methanol (10:90, \(v/v\); 2 mL) that contained 1% acetic acid, the eluate was evaporated under nitrogen stream at 50 \({}^{\circ}\)C and the dry residue was reconstituted with deionized water (150 \(\upmu\)L). The reconstituted eluate was vortexed, sonicated for 5 min and filtrated through a 0.45 \(\upmu\)m filter. Similar sample preparation protocols were developed for the extraction of CAP from skimmed milk and milk powder samples. The authors compared the developed MIP4 SPE-CAP protocol with classic SPE protocol with Oasis HLB cartridges (Waters, Rupperswill, Switzerland). The MISPE protocol displayed higher CAP recoveries, lower throughput time and increased selectivity over the SPE protocol [56]. SupeMIP-CAP SPE cartridges (MIP Technologies, Lund, Sweden) were used for the development of a MISPE-HPLC-UV method for the determination of CAP in honey, urine, milk (raw and semi-skimmed) and plasma samples. The SupeMIP-CAP SPE cartridge was preconditioned with methanol (1 mL) and HPLC grade water (1 mL), loaded with spiked raw milk extract (5 mL) and washed with water (2 \(\times\) 1 mL), acetonitrile-0.5% acetic acid aqueous solution (5:95, \(v/v\); 1 mL), 1% ammonia aqueous solution (2 \(\times\) 1 mL) and acetonitrile-1% ammonia aqueous solution (20:80, \(v/v\), 1 mL). The cartridge was dried under vacuum for 5 min, washed with 2% acetic acid in dichloromethane (2 \(\times\) 1 mL) and dried for 2 min. The analytes were eluted with methanol-acetic acid-water (89:1:10, \(v/v\)/\(v\); 2 \(\times\) 1 mL), the eluate was evaporated under vacuum at 55 \({}^{\circ}\)C and the dry residue was reconstituted with 30% acetonitrile in 10 mM ammonium acetate solution (100 \(\upmu\)L) [57]. SupeMIP-CAP SPE cartridges (MIP Technologies, Lund, Sweden) were also used for the development of a MISPE-gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) method for the determination of CAP in urine, feed water, cow milk and honey samples. The SupeMIP-CAP SPE cartridge was preconditioned with methanol (5 mL) and deionized water (5 mL), loaded with raw cow -milk extract (1 mL) and washed with water (2 mL), 5% acetonitrile in 0.5% acetic acid aqueous solution (1 mL), 1% ammonia aqueous solution (2 mL) and 20% acetonitrile in 1% ammonia aqueous solution (1 mL). The cartridge was dried under vacuum for 5 min, washed with dichloromethane (2 mL) and dried for 1 min. The analytes were eluted with dichloromethane-acetic acid-methanol (89:1:10, \(v/v/v_{i}\) 2 mL) and the eluate was evaporated to dryness at 40 \({}^{\circ}\)C. The SupelMIP-CAP SPE cartridges were compared and found superior to SPE-C18 cartridges (Waters, Milford, MA, USA) in means of sample cleaning capability, simplicity and throughput time [58]. All the reported applications are summarized in Table 1.