## 6 Nano-Particles and Nano-Structures
### Other Metallic Nano-Particles  
The use of AuNPs has become extremely popular in recent years, however, other metallic nano-particles are also available. Monoliths with metallic or metal oxide nano-particles such as nickel-cobalt [124] and titanium dioxide [125; 126], have been prepared via encapsulation (co-polymerization) techniques. In contrast, using a hydrophilic monolithic column (poly(GMA-_co_-trimethylolpropane triacrylate)), silver nanoparticles (SNPs) were trapped in the crevices of the monolithic column. The SNP modified column was effectively used as a detection element for surface enhanced Raman spectroscopy (SERS) [127]. Iron oxide nano-particles (IONPs) have also been used to prepare monolithic media in both column [119] and pipette format [135]. [PERSON] _et al_. prepared poly(GMA-_co_-EDMA) monolithic columns for modification with IONPs [119]. The IONP modified column was applied to the enrichment of phosphopeptides (\(\alpha\)-casein, and \(\beta\)-casein tryptic digests) with MS detection. When compared to commercially available TiO\({}_{2}\) pipette tips, the monolithic column demonstrated greater selectivity. Using ATP, the binding capacity of the monolith was found to be 47.4 mg/mL column volume (86 \(\mu\)mol/mL column volume). The group later extended this technology to the confines of a pipette tip [135]. The quaternary ammonium monomer META was grafted to the monolith, enabling the immobilization of IONPs. The pipette tip was used in the enrichment of phosphopeptides (\(\alpha\)-casein, and \(\beta\)-casein) and was compared to commercially available TiO\({}_{2}\) tips, and again the IONP modified monolithic tip exhibited superior selectivity.  
Using a poly(N-isopropylacrylamide-_co_-GMA-_co_-EDMA) monolith, Li _et al_. immobilized \(\gamma\)-Al\({}_{2}\)O\({}_{3}\) nano-particles [136]. The material was used in the polymer monolith micro-extraction (PMME) procedure of Sudan dyes in red wine samples. Using a subsequent HPLC method (particle packed C\({}_{18}\) column) the dye extract was detected, and the extraction efficiency ranged from 84% to 116%. The nano-particle modified monolith was compared to a polymer only column and to direct HPLC analysis of the wine samples for each dye (Sudan I-IV). A four-fold increase in peak area for the nano-particle modified column relative to the polymer monolith alone and an eight-fold increase relative to direct HPLC analysis were demonstrated. Nano-particles consisting of a composite of metals have also been immobilized to preformed poly(BuMA-_co_-EDMA) columns grafted with VAL or GMA [137]. [PERSON] _et al_. produced nano-flower (NF) immobilized columns [137]. Platinum/palladium NFs consist of a platinum core to which palladium \"petals\" were immobilized. Following column amination, the NFs were immobilized to the monolith surface. The columns were evaluated using chromatography via anion exchange, performed before and following modification. The NF modified column was also successful in catalysis, in the catalytic reduction of Fe(III) to Fe (II), and the catalytic oxidation of NADH to NAD\({}^{+}\). The immobilized NFs demonstrated excellent reproducibility and stability in the presence of strong reducing agents such as sodium borohydride.