title: Determination of melatonin in Acyrthosiphon pisum aphids by liquid chromatography-tandem mass spectrometry.
abstract: Melatonin is a hormone mainly involved in the regulation of circadian and seasonal rhythms in both invertebrates and vertebrates. Despite the identification of melatonin in many insects, its involvement in the insect seasonal response remains unclear. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for melatonin analysis in aphids (Acyrthosiphon pisum) for the first time. After comparing two different procedures and five extraction solvents, a sample preparation procedure with a mixture of methanol/water (50:50) was selected for melatonin extraction. The method was validated by analyzing melatonin recovery at three spiked concentrations (5, 50 and 100 pg/mg) and showed satisfactory recoveries (75-110%), and good repeatability, expressed as relative standard deviation (<10%). Limits of detection (LOD) and quantitation (LOQ) were 1 pg/mg and 5 pg/mg, respectively. Eight concentration levels were used for constructing the calibration curves which showed good linearity between LOQ and 200 times LOQ. The validated method was successfully applied to 26 aphid samples demonstrating its usefulness for melatonin determination in insects. This is -to our knowledge- the first identification of melatonin in aphids by LC-MS/MS.
authors.affiliation: Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain. Electronic address: laura.escriva@uv.es.
authors.forename: Laura
authors.initials: L
authors.lastname: Escrivá
authors.affiliation: Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain.
authors.forename: Lara
authors.initials: L
authors.lastname: Manyes
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Valencia, Spain.
authors.forename: Miquel
authors.initials: M
authors.lastname: Barberà
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Valencia, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Martínez-Torres
authors.affiliation: Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain.
authors.forename: Guiseppe
authors.initials: G
authors.lastname: Meca
mesh_terms: D000818:Animals; D001042:Aphids / Q000737:chemistry*; D002853:Chromatography, Liquid; D005260:Female; D008550:Melatonin / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D008550:Melatonin
keywords: Aphids; LC–MS/MS; Melatonin; Method validation