title: Octadecyl functionalized core-shell magnetic silica nanoparticle as a powerful nanocomposite sorbent to extract urinary volatile organic metabolites.
abstract: In this present study, magnetic Fe3O4@SiO2 nanoparticles (MNPs) functionalized with octadecyl groups (Fe3O4@SiO2-C18 NPs) were synthesized, characterized and employed, for the first time, as powerful nanosorbent to extract endogenous volatile organic metabolites (EVOMs) namely, hexanal, heptanal, decanal, benzaldehyde, 4-heptanone, 5-methyl-2-furfural and phenol, described as potential biomarkers of cancer, from human urine. By using co-precipitation, surface modification methods, the carbon-ferromagnetic nanocomposite was synthesized and characterized by infrared spectrum (IR) and transmission electron microscopy (TEM). By coupling with gas chromatography-mass spectrometry (GC-qMS), a reliable, sensitive and cost-effective method was validated. To test the extraction efficiency of the carbon-ferromagnetic nanocomposite toward urinary EVOMs experimental variables affecting the extraction performance, including nanosorbent amount, adsorption time, elution time, and nature of elution solvent, were investigated in detail. The extraction process was performed by dispersing Fe3O4@SiO2-C18 NPs into working solution containing targeted VOMs, and into urine samples, and then eluted with an adequate organic solvent. The eluate was collected, concentrated and analyzed by GC-qMS. Under the optimized conditions, the LODs and LOQs achieved were in the range of 9.7-57.3 and 32.4-190.9ng/mL, respectively. Calibration curves were linear (r(2)≥0. 988) over the concentration ranges from 0.25 to 250ng/mL. In addition, a satisfying reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 3 and 11%, respectively. The method also afforded satisfactory results in terms of the matrix effect (72.8-96.1%) and recoveries (accuracy) higher than 75.1% for most of the studied EVOMs. The Fe3O4@SiO2-C18 NPs-based sorbent extraction combined with GC-qMS revealed that the new nanosorbent had a strong ability to retain the target metabolites providing a new, reliable and high throughput strategy for isolation of targeted EVOMs in human urine, suggesting their potential to be applied in other EVOMs.
authors.affiliation: CQM, Centro de Química da Madeira, Universidade da Madeira, 9000-390 Funchal, Portugal.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Qiao
authors.affiliation: CQM, Centro de Química da Madeira, Universidade da Madeira, 9000-390 Funchal, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Perestrelo
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: Emilia M
authors.initials: EM
authors.lastname: Reyes-Gallardo
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Lucena
authors.affiliation: Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Cárdenas
authors.affiliation: CQM, Centro de Química da Madeira, Universidade da Madeira, 9000-390 Funchal, Portugal; Centro de Ciências Exatas e de Engenharia da Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Rodrigues
authors.affiliation: CQM, Centro de Química da Madeira, Universidade da Madeira, 9000-390 Funchal, Portugal; Centro de Ciências Exatas e de Engenharia da Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal. Electronic address: jsc@uma.pt.
authors.forename: José S
authors.initials: JS
authors.lastname: Câmara
mesh_terms: D000327:Adsorption; D000447:Aldehydes / Q000652:urine; D014408:Biomarkers, Tumor / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007659:Ketones / Q000652:urine; D057230:Limit of Detection; D058185:Magnetite Nanoparticles; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D000447:Aldehydes; D014408:Biomarkers, Tumor; D007659:Ketones; D058185:Magnetite Nanoparticles; D012822:Silicon Dioxide; C038029:4-heptanone
keywords: Cancer biomarkers; Endogenous volatile organic metabolites (EVOMs); Magnetic nanoparticles; Magnetic solid phase extraction; Urine samples