title: Novel dispersive micro-solid-phase extraction combined with ultrahigh-performance liquid chromatography-high-resolution mass spectrometry to determine morpholine residues in citrus and apples.
abstract: This paper presents a new analytical method for the determination of morpholine residues in citrus and apples using a novel dispersive micro-solid-phase extraction (DMSPE), followed by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Samples were extracted with 1% formic acid in acetonitrile/water (1:1, v/v) and then cleaned up using the DMSPE procedure. Morpholine from the extract was adsorbed to a polymer cation exchange sorbent and eluted with ammonium hydroxide/acetonitrile (3:97, v/v) through a 1 mL syringe with a 0.22 μm nylon syringe filter. All of the samples were analyzed by UHPLC-HRMS/MS on a Waters Acquity BEH hydrophilic interaction chromatography column using 0.1% formic acid and 4 mM ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The method showed good linearity (R(2) > 0.999) in the range of 1-100 μg/L for the analyte. The limit of detection and limit of quantitation values of morpholine were 2 and 5 μg/kg, respectively. The average recoveries of morpholine from the citrus and apple samples spiked at three different concentrations (5, 20, and 100 μg/kg) were in a range from 78.4 to 102.7%.
authors.affiliation: Key Laboratory of Food Safety Risk Assessment, Ministry of Health, China National Center for Food Safety Risk Assessment , Beijing 100021, People's Republic of China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Miao
authors.forename: Jianhong
authors.initials: J
authors.lastname: Zou
authors.forename: Pei
authors.initials: P
authors.lastname: Cao
authors.forename: Ning
authors.initials: N
authors.lastname: Ma
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yongning
authors.initials: Y
authors.lastname: Wu
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002957:Citrus / Q000737:chemistry*; D004350:Drug Residues / Q000737:chemistry / Q000302:isolation & purification; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry; D027845:Malus / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D009025:Morpholines / Q000737:chemistry* / Q000302:isolation & purification*; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D009025:Morpholines; C037574:morpholine
keywords: design of experiments; dispersive micro-solid-phase extraction; fruit; high-resolution mass spectrometry; morpholine