## 5 MIP Applications for the Extraction of Antibiotics in Milk
### Tetracyclines  
Tetracyclines are the first broad-spectrum antibiotic class that was discovered in 1945 from _Streptomyces_ bacteria. They inhibit the bacterial protein synthesis and first tetracyclines to be introduced for clinical use were chlortetracycline and tetracycline. This group of antibiotics is characterized by a four-ring basic structure and can be effective against a variety of microorganisms, such as rickettsia and amoebic parasites. The maximum residue limit in milk according to the Commission Regulation (EU) No. 37/2010 is 100 \(\upmu\)g/kg for chlortetracycline (CTC), oxytetracycline (OTC) and TC, while doxycycline (DC) is not recommended for milk producing animals [1; 2; 3]. MIPs were reported as sorbent materials for the extraction of tetracycline antibiotics from milk samples. Synthesized MIPs were mainly employed in MISPE protocols with reports of a PMME, a SPME and two magnetic dispersion extraction (MDE) protocols. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Analyte** & **Matrix** & **MIP Composite** & \begin{tabular}{c} **Polymerization** \\ **Technique** \\ \end{tabular} & \begin{tabular}{c} **Template-Monomer-Cross** \\ **Linker** \\ \end{tabular} & \begin{tabular}{c} **Extraction-Analysis** \\ **LoD**, **LOQ-CC\({}_{a}\), CC\({}_{b}\)** \\ **(v)** \\ \end{tabular} & **Ref.** \\ \hline FLX, ENO, PEE, NOR, & & & & & & \begin{tabular}{c} LOD (ug/kg) 195-7.35 \\ \end{tabular} & \\ CIP, LVEX, LOM, ENR, & & & & & & & \\ GAT, SPA & & & & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} estriol, extreme, \\ 179-estradiol, OFL, \\ NOR, CIP \\ \end{tabular} } & \multirow{3}{*}{milk} & \multirow{3}{*}{MTMIPs} & \multirow{3}{*}{-} & \begin{tabular}{c} OFL and \\ 179-estradiol-MAA-ECDMA \\ \end{tabular} & \multirow{3}{*}{MSPE-HPLC-UV} & \multirow{3}{*}{-} & \multirow{3}{*}{86.7-94.8} & \multirow{3}{*}{[66]} \\  & & & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} OFL, LOM, CIP, ENR \\ \end{tabular} } & \multirow{3}{*}{milk} & ENR-MIP-HCM & \multirow{3}{*}{sol-gel synthesis} & ENR-MAA and & on-line & LOD (ug/kg) 137-37.74 \\  & & column & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} CIP, DIP, DAN, ENR \\ \end{tabular} } & \multirow{3}{*}{81.9-99.2} & PEE-MIP & \multirow{3}{*}{\begin{tabular}{c} in situ \\ monoliths \\ \end{tabular} } & \multirow{3}{*}{PEE-MAA-DECDMA} & \multirow{3}{*}{PME-HPLC-FLD} & LOD (ug/kg) 4.4-1.6 \\  & & & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} OFL, NOR, ENR \\ \end{tabular} } & \multirow{3}{*}{milk} & \multirow{3}{*}{\
\begin{tabular}{c} hollow \\ OFL-MIPs \\ \end{tabular} } & \multirow{3}{*}{-} & \multirow{3}{*}{OFL-MAA-ECDMA} & \multirow{3}{*}{MSPE/HPLC-UV} & LOD (ug/kg) 20-30} & \multirow{3}{*}{90-102.6} & \multirow{3}{*}{[69]} \\  & & & & & & \\ \hline \multirow{3}{*}{
\begin{tabular}{c} OFL, CIP, LOM \\ \end{tabular} } & \multirow{3}{*}{milk} & \multirow{3}{*}{MMiPs} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{MSPE-HPLC-UV} & LOD (ug/kg) 18-3.2 & \multirow{3}{*}{101.6-124.4} & \multirow{3}{*}{[70]} \\  & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: MIPs applications for the determination of quinolones in milk samples. A MISPE-HPLC-DAD method was developed for determination of CTC, TC, OTC and DC in milk, egg and pork samples. CTC and MAA were dissolved in chloroform (7 mL) and the mixture was shaken for 1 min, sonicated for 15 min and stored at 4 \({}^{\circ}\)C overnight. EGDMA (0.3 mmol) and AlBN (40 mg) were added, the mixture was degassed under nitrogen stream for 10 min, sealed and placed in a water bath at 60 \({}^{\circ}\)C for 24 h. The developed MIP bulk was crushed into particles of (32-60) \(\upmu\)m size, the template was removed by Soxhlet extraction with methanol-acetic acid (8:2, \(v/v\)) for 48 h, and the MIP particles were dried at 110 \({}^{\circ}\)C. CTC-MIPs (30 mg) were packed into an empty cartridge, preconditioned with ultrapure water (3 mL) and methanol (3 mL) and loaded with pretreated spiked milk extract.