title: Quantitative Assessment of Destruxins from Strawberry and Maize in the Lower Parts per Billion Range: Combination of a QuEChERS-Based Extraction Protocol with a Fast and Selective UHPLC-QTOF-MS Assay.
abstract: The entomopathogenic fungus Metarhizium brunneum is widely applied as a biological pest control agent. Consequently, its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, for example, in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to monitor the presence of secreted destruxins in two model food plants for the application of this fungal biocontrol agent, namely, strawberry and maize. The liquid chromatography-mass spectrometric assay for destruxin trace analysis is combined with a novel QuEChERS-based extraction protocol. The whole assay was optimized for the application in these crops, and it allows quantitative analysis of the major M. brunneum metabolites destruxin A, 1, destruxin B, 2, and destruxin E, 3, down to the parts per billion range. In strawberry, limits of quantitation (LOQs) were found to be <2.0 ppb for all analytes; in maize LOQs were found to be <3.2 ppb for destruxin A and destruxin B. Destruxin E showed a distinctive loss of recovery in maize and was excluded from further quantitative analysis in this crop. For both crops assay linearities ranged from the LOQs to 100 ppb, interassay repeatabilities (RSD) were found to be better than 16.4%, and accuracies ranged from 83.5 to 105.3% (assessed at four spiking levels between 5 and 75 ppb).
authors.affiliation: †Institute of Pharmacy, Department of Pharmacognosy, CCB - Centrum of Chemistry and Biomedicine, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.|‡Institute of Microbiology, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: Judith
authors.initials: J
authors.lastname: Taibon
authors.affiliation: †Institute of Pharmacy, Department of Pharmacognosy, CCB - Centrum of Chemistry and Biomedicine, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Sonja
authors.initials: S
authors.lastname: Sturm
authors.affiliation: †Institute of Pharmacy, Department of Pharmacognosy, CCB - Centrum of Chemistry and Biomedicine, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.|#Institute of Medical and Chemical Laboratory Diagnostics (ZIMCL), University Hospital Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Seger
authors.affiliation: ‡Institute of Microbiology, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: Hermann
authors.initials: H
authors.lastname: Strasser
authors.affiliation: †Institute of Pharmacy, Department of Pharmacognosy, CCB - Centrum of Chemistry and Biomedicine, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Hermann
authors.initials: H
authors.lastname: Stuppner
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D047630:Depsipeptides / Q000737:chemistry* / Q000302:isolation & purification; D031985:Fragaria / Q000737:chemistry* / Q000382:microbiology; D005656:Fungal Proteins / Q000737:chemistry* / Q000302:isolation & purification; D009183:Mycotoxins / Q000737:chemistry / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D003313:Zea mays / Q000737:chemistry* / Q000382:microbiology
chemical_list: D047630:Depsipeptides; D005656:Fungal Proteins; D009183:Mycotoxins; C040423:destruxin A; C040424:destruxin B; C040425:destruxin E
keywords: Metarhizium; QuEChERS; UHPLC-QTOF-MS; crops; destruxin; risk assessment