In this study, novel open‐tubular nano‐columns with highly hydrophobic stationary phase were prepared via the surface graft polymerization of polyhedral oligomeric silsesquioxane‐methacrylate and 2‐vinylnaphthalene in a narrow capillary (i.e., 20 μm i.d. In this preparation, polyhedral oligomeric silsesquioxane‐methacrylate was used as a reactive and stable monomer while 2‐vinylnaphthalene imparts hydrophobic character for the stationary phase. Toluene and dodecanol were used as the porogenic solvent. Scanning electron microscope images of the columns showed that polyhedral oligomeric silsesquioxane and 2‐vinylnaphthalene were bound to the surface of the capillary. The chromatographic characterization of the open‐tubular columns was performed using homologous alkylbenzenes, including toluene, ethylbenzene, propylbenzene, and butylbenzene. The satisfactory separation of alkylbenzenes could be obtained using the final open‐tubular column with 17.1% of 2‐ vinylnaphthalene. Theoretical plates number up to 34000 plates/m in the isocratic mode for ethylbenzene were achieved. The open‐tubular column with various lengths was used for the separation of intact proteins in nano‐liquid chromatography, allowing a notable change in the retention time of each intact protein, including ribonuclease A, Lysozyme, and α‐Chymotryp A. The final open‐tubular column was then applied to the peptide separation of trypsin‐digested cytochrome C. It was shown that the open‐tubular column yielded a high‐resolution analysis of peptides, providing a high peak capacity of up to 1000.

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Coenzyme Q10 (CoQ10) is a vital substance found throughout body. It helps convert food into energy and is eaten small amounts in foods. CoQ10 has gained great interest in recent years as a potential candidate for the treatment of various diseases. The content of CoQ10 in food samples is a crucial quality index for foods. Therefore, the development of sensitive separation and quantification method for determining the amount of CoQ10 in various samples, especially in foods, is an important issue, especially for food nutrition. In this study, a new, miniaturized monolithic column was developed and applied for the determination of CoQ10 in pistachio samples by nano-liquid chromatography (nano-LC). The monolithic column with a 50 µm i.d. was prepared by in situ polymerization using laurylmethacrylate (LMA) as the main monomer and ethylene dimethacrylate (EDMA) as the crosslinker. Methanol (MeOH) and polyethyleneglycol (PEG) were used as porogenic solvents. The final monolithic column was characterized by using scanning electron microscopy (SEM) and chromatographic analyses. The monolithic column with a 50 µm i.d. was applied to the analysis of CoQ10 in pistachio samples in nano-LC. This analytical method was validated by means of sensitivity, linearity, precision, recovery, and repeatability. The LOD and LOQ values were 0.05 and 0.48 µg/kg, respectively. The developed method using the monolithic column was optimized to achieve very sensitive analyses of CoQ10 content in the food samples. The applicability of the method was successfully demonstrated by the analysis of CoQ10 in pistachio samples.

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