Date of Graduation

Fall 2022


Master of Science in Chemistry


Chemistry and Biochemistry

Committee Chair

Cyren Rico


Plants are exposed to emerging contaminants including nanoparticles, due to the novel but wide uses of these materials. However, researchers have shown contradicting effects of CeO2-NPs on barley grains with focus mostly on concentration effects and not sizes of these CeO2-NPs. Therefore, this study aimed at comparing the effects of 0nm (control), 8nm, and 40nm (250 mg CeO2-NPs/kg soil) on the metabolite profile of barley grains. GC-FID and GC-QTOF-MS were used to measure fatty acid contents and metabolomic changes respectively. GC-FID analysis revealed that palmitic acid, oleic acid, linoleic acid, and the total fatty acid concentrations were not affected, although linolenic acid was increased by 8nm CeO2-NPs. Interestingly, most sugar metabolites (UDP-N-acetylglucosamine, sorbitol, arabitol, digalacturonic acid, lyxitol, 1,5-anhydroglucitol, and ribose) were decreased by 8nm CeO2-NPs but increased by 40nm CeO2-NPs except 1-Kestose. Other sugars (erythritol, beta-gentibiose, glucoheptulose, N-acetylmannosamine, methylmaleic acid, and maltitol) were decreased by both CeO2-NPs except maltotriitol, ribitol, and glycerol. Amino acid metabolites (N-acetylserine and alanine) were also decreased by both CeO2-NPs while tyramine was increased. Antioxidant metabolites (ferulic acid and vanillic acid) were increased in treated grains compared to control, while 4-hydroxycinnamic acid was decreased by both 8nm and 40nm CeO2-NPs. Surprisingly, all fatty acid metabolites were increased by both sizes of CeO2-NPs except pentadecanoic acid treated with 8nm CeO2-NPs. Overall, these findings indicate that CeO2-NPs can have size-dependent but subtle effects on the metabolite profile and biochemical pathways of barley grains. Future studies should investigate if those biochemical changes can have effects in the succeeding generations.


amino acid, antioxidant, fatty acid, metabolites, plants, sugar

Subject Categories

Analytical Chemistry | Environmental Chemistry


© Naum Jepkemei Kirwa

Available for download on Tuesday, December 16, 2025

Open Access