Vergara-Barberán, MaríaSimó-Alfonso, Ernesto F.Herrero-Martínez, José ManuelBenavente Moreno, Fernando J. (Julián)2023-06-162023-06-1620230039-9140https://hdl.handle.net/2445/199378An on-line aptamer affinity solid-phase extraction capillary electrophoresis-mass spectrometry (AA-SPE-CE-MS) method was developed to purify, preconcentrate, separate, and characterize the milk allergenic protein β-lactoglobulin (β-LG) in food samples. The sorbent to pack into the SPE microcartidges was prepared by immobilizing an aptamer against β-LG onto magnetic bead particles. After optimizing the SPE-CE-MS method, the sample (ca. 75 µL) was loaded in separation background electrolyte (BGE, 2 M acetic acid pH 2.2), while a solution of 100 mM NH4OH (pH 11.2) (ca. 100 nL) was used for the protein elution. The linearity of the method ranged between 0.1 and 20 µg·mL-1 and the limit of detection (LOD) was 0.05 µg·mL-1, which was 200 times lower than by CE-MS. The method was repeatable in terms of relative standard deviation (RSD) for migration times and peak areas (< 0.5 % and 2.4 %, respectively) and microcartridge lifetime was more than 25 analyses. The applicability of the method for the determination of low levels of β-LG was shown by analyzing milk-free foods (i.e. a 100 % cocoa dark chocolate, a hypoallergenic formula for infants, and a dairy-free white bread) and milk-containing white breads. Results were satisfactory in all cases, thus demonstrating the great potential of the developed method for accurate food safety and quality control.application/pdfengcc-by-nc-nd (c) Vergara-Barberán, María et al., 2023https://creativecommons.org/licenses/by-nc-nd/4.0/Espectrometria de massesLletElectroforesi capil·larMass spectrometryMilkCapillary electrophoresisinfo:eu-repo/semantics/article7334032023-06-16info:eu-repo/semantics/openAccess