title: Quantitative analysis of dicamba residues in raw agricultural commodities with the use of ion-pairing reagents in LC-ESI-MS/MS.
abstract: A sensitive and selective HPLC-MS/MS method was developed for the quantitative analysis of dicamba residues in raw agricultural commodities (RACs). Instead of analysis in the traditionally used negative electrospray ionization (ESI) mode, these anionic compounds were detected in positive ESI with the use of ion-pairing reagents. In this approach, only a small amount (60µM) of a commercially available dicationic ion-pairing reagent was introduced into the post-column sample stream. This method has been validated in six different types of RACs including corn grain, corn stover, cotton seed, soybean, soy forage and orange with satisfactory quantitative accuracy and precision. The limits of quantitation (LOQ) values for these analytes were 1.0 to 3.0µg/kg. The standard curves were linear over the range of the tested concentrations (3.0 to 500µg/kg), with correlation coefficient (r) values≥0.999. Evaluation of ionization effects in RAC matrix extracts using diluent blanks for comparison showed no significant matrix effects were present.
authors.affiliation: Monsanto Company, St Louis, MO, United States; University of Texas at Arlington, Arlington, TX, United States.
authors.forename: Hongyue
authors.initials: H
authors.lastname: Guo
authors.affiliation: Monsanto Company, St Louis, MO, United States.
authors.forename: Leah S
authors.initials: LS
authors.lastname: Riter
authors.affiliation: Monsanto Company, St Louis, MO, United States.
authors.forename: Chad E
authors.initials: CE
authors.lastname: Wujcik
authors.affiliation: University of Texas at Arlington, Arlington, TX, United States.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Armstrong
mesh_terms: D002851:Chromatography, High Pressure Liquid; D032084:Citrus sinensis; D003996:Dicamba / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry; D006540:Herbicides / Q000032:analysis*; D007202:Indicators and Reagents / Q000737:chemistry; D010573:Pesticide Residues / Q000032:analysis*; D011759:Pyrrolidines / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D013025:Glycine max; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D003313:Zea mays
chemical_list: D006540:Herbicides; D007202:Indicators and Reagents; D010573:Pesticide Residues; D011759:Pyrrolidines; D003996:Dicamba
keywords: Dicamba; HPLC–MS/MS; Ion-pairing reagent; Raw agricultural commodities (RACs); Residue analysis