title: Determination of alkaloids in onion nectar by micellar electrokinetic chromatography.
abstract: Nectar is the most important floral reward offered by plants to insects. Minor components such as alkaloid compounds in nectar affect bee foraging, with great influence in seed production. CE is an advantageous tool for the analysis of unexplored samples such as onion nectar due to the limited amounts of samples. Considering the importance of these compounds, a simultaneous determination of nicotine, theophylline, theobromine, caffeine, harmaline, piperine in onion nectar by MEKC-UV is herein reported. The extraction of alkaloid compounds in nectar was performed by SPE using a homemade miniaturized column (C18 ). Effects of several important factors affecting extraction efficiency as well as electrophoretic performance were investigated to acquire optimum conditions. Under the proposed conditions, the analytes can be separated within 15 min in a 50 cm effective length capillary (75 μm id) at a separation voltage of 20 kV in 20 mmol/L sodium tretraborate, 100 mmol/L SDS. The amount of sample requirement was reduced up to 2000 times, when compared to traditional methods, reaching limits of detection as low as 0.0153 ng/L. For the first time, this study demonstrates that there are marked qualitative and quantitative differences in nectar alkaloids between open pollinated and male sterile lines (MSLs) and also within MSLs.
authors.affiliation: Instituto de Biología Agrícola de Mendoza (IBAM-CONICET), Alte, CP, Mendoza, Argentina.
authors.forename: Verónica
authors.initials: V
authors.lastname: Carolina Soto
authors.affiliation: Instituto Nacional de Tecnología Agropecuaria (INTA), Mendoza, Argentina.
authors.forename: Viviana Patricia
authors.initials: VP
authors.lastname: Jofré
authors.affiliation: Instituto Nacional de Tecnología Agropecuaria (INTA), Mendoza, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.|Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina.
authors.forename: Claudio Romulo
authors.initials: CR
authors.lastname: Galmarini
authors.affiliation: Instituto de Biología Agrícola de Mendoza (IBAM-CONICET), Alte, CP, Mendoza, Argentina.
authors.forename: María Fernanda
authors.initials: MF
authors.lastname: Silva
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D057230:Limit of Detection; D019697:Onions / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D000470:Alkaloids
keywords: Allium cepa L; Male sterility; Nectar alkaloids; Seed yield