Publications by authors named "Jon W Wong"

Background: Cost-effective multi-residue pesticide methods with a broad detection scope are desired for risk-based monitoring programs.

Objective: The aim was to evaluate the nDATA (non-target Data Acquisition for Target Analysis) workflow using UHPLC/ESI quadrupole-Orbitrap (Q-Orbitrap) mass spectrometry and semi-quantitate 1094 pesticides in fruits and vegetables.

Methods: Pesticide extracts from fresh produce were prepared using the QuEChERS procedure.

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Article Synopsis
  • A collaborative study involving 25 laboratories assessed the effectiveness of a nontarget data acquisition (nDATA) workflow for screening pesticides in high moisture produce using advanced liquid chromatography-high-resolution mass spectrometry techniques.* -
  • The study employed a quick and efficient sample extraction method (QuEChERS) and focused on identifying 51 pesticides, ensuring accuracy through strict criteria for retention time and mass errors.* -
  • Results showed high consistency in pesticide elution profiles among laboratories and low false positive/negative rates (1.1%, 0.7%, and 0.1% respectively), indicating the potential for reliable routine analysis after further evaluations.*
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High sample throughput and effective multiresidue methods for screening, quantitation, and identification are desired for the analysis of a large number of pesticides in routine monitoring programs for food safety. This study was designed to explore the use of an UHPLC/ESI Q-Orbitrap nontarget data acquisition for target analysis (nDATA) workflow for screening 655 pesticides and quantifying a small group of 46 most likely incurred pesticide residues in fruits and vegetables in a single analysis. High-resolution mass spectrometers such as the Q-Orbitrap offer unique applications for pesticide analysis using full MS scan with data independent acquisition (DIA) or all ion fragmentation (AIF) scan.

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Background: Effective and expansive methods for multiresidue pesticide analysis are desired for routine monitoring programs. These methods are complex, especially when several hundred pesticides are involved.

Objective: Two approaches to sort data and identify isomers and isobaric ions in pesticide mixtures were evaluated to determine whether they could be differentiated by mass resolving power and/or chromatographic resolution.

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A non-target data acquisition for target analysis (nDATA) workflow based on accurate mass measurements using UHPLC/ESI Q-Orbitrap full MS-data-independent acquisition and a compound database was developed to screen pesticide residues in fruit and vegetable samples. The compound database of 845 pesticides was built from dd-MS (data-dependent acquisition) product ion spectral data and LC retention times of individual pesticide standards. MS spectra of samples were acquired using multiplexing data-independent acquisition (mDIA) and variable data-independent acquisition (vDIA).

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This perspective discusses the use of liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) for multiresidue analysis of pesticides in foods and agricultural commodities. HRMS has the important distinction and advantage of mass-resolving power and, therefore, requires different concepts, experiments, and guidance for screening, identification, and quantitation of pesticides in complex food matrices over triple quadrupole mass spectrometry. HRMS approaches for pesticide screening, including full-scan experiments in conjunction with tandem mass spectrometry (MS/MS) experiments, are described.

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This paper presents a multi-class target screening method for the detection of 105 veterinary drug residues from 11 classes in milk using ultra-high performance liquid chromatography electrospray ionization quadrupole Orbitrap mass spectrometry (UHPLC/ESI Q-Orbitrap). The method is based on a non-target approach of full mass scan and multiplexing data-independent acquisition (Full MS/mDIA). The veterinary drugs include endectocides, fluoroquinolones, ionophores, macrolides, nitroimidazole, NSAIDs, β-lactams, penicillins, phenicols, sulfonamides, and tetracyclines.

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An analytical method was developed and validated for the determination of 40 veterinary drugs in various milk-based powders. The method involves acetonitrile/water extraction, solid-phase filtration for lipid removal in fat-containing matrices, and analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limits of quantitation (LOQ) ranged from 0.

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A semiautomated qualitative method for target screening of 448 pesticide residues in fruits and vegetables was developed and validated using ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC/ESI Q-Orbitrap). The Q-Orbitrap Full MS/dd-MS (data dependent acquisition) was used to acquire product-ion spectra of individual pesticides to build a compound database or an MS library, while its Full MS/DIA (data independent acquisition) was utilized for sample data acquisition from fruit and vegetable matrices fortified with pesticides at 10 and 100 μg/kg for target screening purpose. Accurate mass, retention time and response threshold were three key parameters in a compound database that were used to detect incurred pesticide residues in samples.

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A collaborative study was conducted to evaluate stable isotope dilution assay (SIDA) and LC-MS/MS for the simultaneous determination of aflatoxins B, B, G, and G; deoxynivalenol; fumonisins B, B, and B; ochratoxin A; HT-2 toxin; T-2 toxin; and zearalenone in foods. Samples were fortified with 12 C uniformly labeled mycotoxins (C-IS) corresponding to the native mycotoxins and extracted with acetonitrile/water (50:50 v/v), followed by centrifugation, filtration, and LC-MS/MS analysis. In addition to certified reference materials, the six participating laboratories analyzed corn, peanut butter, and wheat flour fortified with the 12 mycotoxins at concentrations ranging from 1.

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The presence of mycotoxins (such as aflatoxins, deoxynivalenol, fumonisins, and patulin) is routinely monitored by the U.S. Food and Drug Administration (FDA) to ensure that their concentrations in food are below the levels requiring regulatory action or advisories.

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A simplified sample preparation method in combination with gas chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) analysis was developed and validated for the simultaneous determination of 227 pesticides in green tea, ginseng, gingko leaves, saw palmetto, spearmint, and black pepper samples. The botanical samples were hydrated with water and extracted with acetonitrile, magnesium sulfate, and sodium chloride. The acetonitrile extract was cleaned up using solid phase extraction with carbon-coated alumina/primary-secondary amine with or without C18.

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This paper presents the development and validation of a multiclass method for the analysis of veterinary drug residues in milk using ultrahigh performance liquid chromatography electrospray ionization quadrupole Orbitrap mass spectrometry (UHPLC/ESI Q-Orbitrap). The 12 classes of veterinary drugs (a total of 125) included in this study were endectocides, fluoroquinolones, ionophores, macrolides, nitroimidazole, NSAIDs, β-lactams, penicillins, phenicols, sulfonamides, tetracyclines, and aminoglycosides. Veterinary drug residues in milk were extracted using a modified salting-out supported liquid extraction (SOSLE) method, which entailed the precipitation of milk proteins using an extraction buffer (oxalic acid and EDTA, pH 3) and acetonitrile, a salting-out acetonitrile/water phase separation using ammonium sulfate, and solid-phase extraction (SPE) using polymeric reversed-phase sorbent cartridges.

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Black, green, white, and Oolong teas, all derived from leaves of Camellia sinensis, are widely consumed throughout the world and represent a significant part of the beverages consumed by Americans. A gas chromatography-triple quadrupole-based method, previously validated for pesticides on dried botanical dietary supplements, including green tea, was used to measure pesticides fortified into black and green teas at 10, 25, 100, and 500 μg/kg. Teas from 18 vendors of tea products were then surveyed for pesticides.

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This study used two LC columns of different adsorbents and liquid chromatography-electrospray ionization-high-resolution mass spectrometry to study the relationship between matrix effects (ME), the LC separations, and elution patterns of pesticides and those of matrix components. Using calibration standards of 381 pesticides at three dilution levels of 1×, 1/10×, and 1/100×, 108 samples were prepared in solvent and five different sample matrices for the study. Results obtained from principal component analysis and slope ratios of calibration curves provided measurements of the ME and showed the 1/100× sample dilution could minimize suppression ME for most pesticides analyzed.

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Ultrahigh-performance liquid chromatography using positive electrospray ionization and quadrupole orbital ion trap high-resolution mass spectrometry was evaluated for analyzing mycotoxins in finished cereal and nut products. Optimizing the orbital ion trap mass analyzer in full-scan mode using mycotoxin-fortified matrix extracts gave mass accuracies, δM, of < ± 2.0 ppm at 70,000 full width at half maximum (FWHM) mass resolution (RFWHM).

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This paper presents an application of ultrahigh-performance liquid chromatography electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC/ESI Q-Orbitrap MS) for the determination of 451 pesticide residues in fruits and vegetables. Pesticides were extracted from samples using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. UHPLC/ESI Q-Orbitrap MS in full MS scan mode acquired full MS data for quantification, and UHPLC/ESI Q-Orbitrap Full MS/dd-MS(2) (i.

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We developed a stable isotope dilution assay with liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine multiple mycotoxins in baby foods and animal feeds. Samples were fortified with [(13)C]-uniformly labeled mycotoxins as internal standards ([(13)C]-IS) and prepared by solvent extraction (50% acetonitrile in water) and filtration, followed by LC-MS/MS analysis. Mycotoxins in each sample were quantitated with the corresponding [(13)C]-IS.

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Stable isotope dilution with LC/MSIMS was used to determine the following 11 mycotoxins in food grade gums: aflatoxins B1, B2, G1, and G2; deoxynivalenol; fumonisins B1, B2, and B3; ochratoxin A; T-2 toxin; and zearalenone. Samples were fortified with 11 [13C]-uniformly labeled internal standard ([13C]-IS) mycotoxins that corresponded to the 11 target mycotoxins and extracted by acetonitrile-water (4 + 1, v/v), followed by LC/MS/MS analysis. Mycotoxins were quantitated with the fortified [13C]-IS in each sample.

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A dopant-assisted atmospheric pressure photoionization (APPI) with liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to determine patulin in apple juice and apple-based food. Different dopants, dopant flow rates, and LC separation conditions were evaluated. Using toluene as the dopant, the LC-APPI-MS/MS method achieved a linear calibration from 12.

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A stable isotope dilution assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of 12 mycotoxins, aflatoxins B₁, B₂, G₁, G₂, and M₁, deoxynivalenol, fumonisins B₁, B₂, and B₃, ochratoxin A, T-2 toxin, and zearalenone, in milk-based infant formula and foods. Samples were fortified with 12 ¹³C uniformly labeled mycotoxins ([¹³C]-mycotoxins) that correspond to the 12 target mycotoxins and prepared by dilution and filtration, followed by LC-MS/MS analysis. Quantitation was achieved using the relative response factors of [¹³C]-mycotoxins and target mycotoxins.

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Mycotoxins in foods have long been recognized as potential health hazards due to their toxic and carcinogenic properties. A simple and rapid method was developed to detect 26 mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, and ergot alkaloids) in corn, rice, wheat, almond, peanut, and pistachio products using high-performance liquid chromatography-triple-quadrupole mass spectrometry. Test portions of homogenized grain or nut products were extracted with acetonitrile/water (85:15, v/v), followed by high-speed centrifugation and dilution with water.

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Dietary supplements form an increasing part of the American diet, yet broadly applicable multiresidue pesticide methods have not been evaluated for many of these supplements. A method for the analysis of 310 pesticides, isomers, and pesticide metabolites in dried botanical dietary supplements has been developed and validated. Sample preparation involved acetonitrile:water added to the botanical along with anhydrous magnesium sulfate and sodium chloride for extraction, followed by cleanup with solid-phase extraction using a tandem cartridge consisting of graphitized carbon black (GCB) and primary-secondary amine sorbent (PSA).

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An automated dispersive solid phase extraction (dSPE) cleanup procedure as part of the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method, coupled with liquid chromatography-tandem mass spectrometry using electrospray ionization in positive mode, was used for the simultaneous analysis of 236 pesticides in three dried powdered botanical dietary supplements (ginseng, saw palmetto, and gingko biloba). The procedure involved extraction of the dried powdered botanical samples with salt-out acetonitrile/water extraction using anhydrous magnesium sulfate and sodium chloride, followed by an automated dSPE cleanup using a mixture of octadodecyl- (C18) and primary-secondary amine (PSA)-linked silica sorbents and anhydrous MgSO4 and online LC-MS/MS analysis. Dynamic multiple-reaction monitoring (DMRM) based on the collection of two precursor-to-product ion transitions with their retention time windows was used for all of the targeted pesticides and the internal standard.

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