title: Determination of glyphosate in surface water with high organic matter content.
abstract: In this paper, we investigate the sample preparation and analysis process in order to achieve adequate results for surface water collected from rivers that flow through swamps and are consequently rich in organic matter. We show that matrix effects in glyphosate determination can be reduced by optimizing sample volume, liquid chromatography (LC) mobile phase buffer concentration and pH as well as gradient speed. Also, aspects of derivatization procedure (borate buffer concentration, fluorenylmethyloxycarbonyl chloride concentration) and their influence on accuracy are considered in detail. We encountered a cross-talk effect in the mass spectra, interfering with quantization during analysis, which was removed by optimizing MS parameters. As a result it was demonstrated that isotope-labelled internal standard with just one13C atom is sufficient for the analysis.All these aspects were found to strongly impact the accuracy of the glyphosate determination but have received little or no attention in earlier works. We propose a reliable solid phase extraction and LC/ESI/MS/MS method for determination of glyphosate in organic-rich waters and demonstrate that LoD can be decreased by about two times using an ESI nebulizer with a modified design.
authors.affiliation: Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
authors.forename: Vahur
authors.initials: V
authors.lastname: Toss
authors.affiliation: Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
authors.forename: Ivo
authors.initials: I
authors.lastname: Leito
authors.affiliation: Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 62, 51014, Tartu, Estonia.
authors.forename: Sergei
authors.initials: S
authors.lastname: Yurchenko
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 5, 51014, Tartu, Estonia.
authors.forename: Rene
authors.initials: R
authors.lastname: Freiberg
authors.affiliation: Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia. anneli.kruve@ut.ee.
authors.forename: Anneli
authors.initials: A
authors.lastname: Kruve
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D004784:Environmental Monitoring; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis; D006540:Herbicides / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D014874:Water Pollutants, Chemical; D000097797:Glyphosate
keywords: Derivatization; Electrospray ionization; Glyphosate; Mass spectrometry; Matrix effect