## 3 Applications in Food Safety
### LC and GC Separations  
Monolithic columns are gaining popularity, as they have been demonstrated to be a good alternative to particle-packed columns in HPLC. These columns possess some unique characteristics that make them an excellent tool in the analytical laboratory. When compared to conventional particle-packed columns, they provide a lower pressure drop and higher total porosity and separation efficiency. Monoliths are frequently designed to be used for liquid chromatography (LC) and capillary electrochromatography (CEC). The major chromatographic features of monolithic columns arise from their mesopore/macropore structure, with low back-pressure, even at high flow rates. The drawbacks of these columns include the existence of only a few stationary phases and lower column-to-column and batch-to-batch reproducibility. However, some studies have already demonstrated the high degree of reproducibility of some last-generation monolithic columns [11]. Fast separations in the second dimension of two-dimensional LC \(\times\) LC are achieved using short and efficient columns, including monolithic columns, which do not require ultrahigh pressures to provide high efficiency at high flow rates [57]. Fast LC in the minimum possible time is a major trend in modern food analytical chemistry. So far, only UHPLC methods using sub-2-\(\upmu\)m particulate columns fulfil this demand, offering analysis times in the 5-min range. Alternative solutions employ a conventional HPLC instrumentation with \begin{table}
\begin{tabular}{|c|c|c|c|c|c|} \hline
**Compound** & **Matrix** & **Monolith** & **Application** & **Reference** & **Observations** \\ \hline Quinoxaline and sulfonamide antimicrobials: sulfaquoxaline, sulfamethoxazole, sulfamethoxazoline, sulfametoxydiaz, sulfametoxydiaz, mequindox, quinocetone & Chicken, pork, egg sulfametoxydiaz, mequindox, quinocetone & MIP (MAA, EGDMA) & MIMCC & [54] & Fused-silica capillaries \\ \hline PCBs: 28,52,101,118,138,153,180 & Red wine & Poly(BMA-co-EGDMA) & PMME & [55] & Functionalize d with allylamine-\(\upbeta\)-cyclodextrintrin and nano-cuprous oxide \\ \hline \multirow{3}{*}{Azo-dyes: Sudan I, II, III, IV} & Tomato sauce, egg yolk & Poly(OM/VI-DVB) & SPME & [56] & Fibers \\ \hline \end{tabular}  
* Abbreviations: AM, acrylamide; AMPS, 2-acrylamido-2-methyl-1-propanesulfonic acid; APCI, atmospheric pressure chemical ionization; BMA, butyl methacrylate; DVB, divinylbenzene; EDMA, ethylene dimethacrylate; LC, liquid chromatography; MAA, methacrylic acid; MAPS, \(\gamma\)-methacryloxypropyltrimethoxysilane; MICEC, molecularly-imprinted capillary electrochromatography; MIMCC, molecularly-imprinted monolithic capillary columns; MIP, molecularly-imprinted polymer; MIPMME, molecularly-imprinted polymer monolith microextraction; MS, mass spectrometry; OM, octadecyl methacrylate; PHAs, polycyclic aromatic hydrocarbons; PCBs, polychlorinated biphenyls; PT-MIPMME, pipette tip-based molecularly-imprinted polymer monolith microextraction; PMME, polymer monolith microextraction; SMA, stearyl methacrylate; SPME, solid-phase microextraction; SBSE, Stir bar sorptive extraction; VI, vinylimidazole; 4-VP, 4-vinylpyridine.  
\end{table} 
Table 1: _Cont._monolithic columns, allowing faster analysis than the particle-packed columns of the same length at the same operating pressure [9, 57]. Recently, a simple and sensitive method for the quantification of malachite green in fish feed was developed using a commercial LC C18 monolithic column in combination with mass spectrometry [44]. [PERSON] _et al._, 2014, measured two macrolide antibiotics in various animal tissues (muscle, liver), eggs, milk, baby food and formulae using the same monolithic column, producing well-resolved peaks with very high sensitivity within a reasonable analytical time (10 min) [48]. Samples were injected directly into the chromatographic system with no previous treatment other than homogenization, dilution and filtration.