Publications by authors named "Jonathan Grandy"

Per- and polyfluoroalkyl substances (PFAS), in the polymeric form, have been used extensively in functional textiles, including firefighter's turnout gear (e.g., jackets and pants), where PFAS are applied to confer oil and water resistance.

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The recent increase in legality of . has led to interest in developing new varieties with unique aromatic or effect-driven traits. Selectively breeding plants for the genetic stability and consistency of their secondary metabolite profiles is one application of phenotyping.

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L. produces a wide variety of volatile secondary metabolites that contribute to its unique aroma. The major volatile constituents include monoterpenes, sesquiterpenes, and their oxygenated derivates.

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A thin film-solid phase microextraction (TF-SPME) method was developed to test for 5 individual polychlorinated n-alkanes (PCAs) from commercial cod liver oil samples. This was accomplished by preparing a novel aluminum supported, hydrophilic-lipophilic balance/polydimethylsiloxane (HLB/PDMS) TF-SPME device that enabled direct immersion extraction from fish oil. Matrix-matched calibration gave a linear range from 0.

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A novel magnetic blade spray-tandem mass spectrometry (MBS-MS/MS) assay was developed and optimized, and its performance was characterized for the analysis of 204 pesticides from wastewater treatment facility (WWTF) process water. These results were compared and experimentally validated with an untargeted, high-resolution MS (HRMS) approach that employed liquid chromatography (LC)-amenable thin-film microextraction (TFME) devices to further elucidate the fate of pesticides through the WWTF process. As a result of our optimizations, we report an optimized workflow with an extraction time of 10 min, 150 μg of magnetic HLB particles, and 5 s of desorption.

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This work presents the development and validation of novel thin film solid phase micro extraction (TF-SPME) based standard gas generating vials suitable for repeatable generation of gaseous standards for GC-MS analysis and quality control. The vials were developed using carbon mesh membranes loaded with pure polydimethylsiloxane (PDMS), divinylbenzene (DVB/PDMS), hydrophilic-lipophilic balance (HLB/PDMS), and carboxen (Car/PDMS) sorbents that were then spiked with modified McReynolds standards including benzene, 2-pentanone, 1-nitropropane, pyridine, 1-pentanol, octane, dodecane, and hexadecane. Sorbent strength was determined to follow the aforementioned order, with pure PDMS presenting the weakest sorption capabilities and Car/PDMS the strongest.

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Pyrethroids insecticides may constitute a major hazard to honeybees, leading to colony collapse disorder. However, the determination of pyrethroids in honey has remained a challenging undertaking for analysts to date due to the high complexity of this matrix as well as the MRLs. This paper presents a fully automated method to overcome matrix influences using matrix-compatible overcoated SPME fiber for quantitative analysis of pyrethroids in diluted honey by GC-MS.

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To simplify on-site water sampling and screening, particularly in hard-to-reach or dangerous sites, a drone equipped with a hydrophilic-lipophilic balance (HLB), thin-film solid-phase microextraction (TF-SPME) sampler was developed. The drone-based sampler was shown to protect the sorbent phase from external contamination while preventing any detectable loss of components of a spiked modified McReynolds mixture on the membrane in the sampler for at least 10 min. HLB/poly(dimethylsiloxane) (PDMS) membranes deployed in flight on the drone sampler were demonstrated to extract disinfection by-products, including trichloromethane, dichloroacetonitrile, 1,1,1-trichloro-2-propanone, 2,2,2-trichloroethanol, benzonitrile, and benzyl nitrile, from hot tub water.

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A semi-automated and sensitive method was developed for simultaneous determination of the six most consumed artificial sweeteners (AS) in surface waters using thin-film solid-phase microextraction (TF-SPME) and high-performance liquid chromatography (HPLC). A triple quadrupole mass spectrometer and an electrospray ionization source (ESI-MS) run in negative ionization and multiple reaction monitoring modes were employed for instrumental analysis. The TF-SPME method was optimized for the extraction phase, sample pH, desorption solvent, extraction time, and desorption time.

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Current methods for biochemical and biogeochemical analysis of the deep-sea hydrothermal vent ecosystems rely on water sample recovery, or in situ analysis using underwater instruments with limited range of analyte detection and limited sensitivity. Even in cases where large quantities of sample are recovered, labile dissolved organic compounds may not be detected due to time delays between sampling and preservation. Here, we present a novel approach for in situ extraction of organic compounds from hydrothermal vent fluids through a unique solid phase microextraction (SPME) sampler.

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Detection of biomarkers in exhaled breath has been gaining increasing attention as a tool for diagnosis of specific diseases. However, rapid and accurate quantification of biomarkers associated with specific diseases requires the use of analytical methods capable of fast sampling and preconcentration from breath matrix. In this regard, solid phase microextraction and needle trap technology are becoming increasingly popular in the field of breath analysis due to the unique benefits imparted by such methods, such as the integration of sampling, extraction, and preconcentration in a single step.

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The present study introduces a mechanically robust, sealable SPME sampler for the on-site sampling and extraction of a wide range of untargeted pollutants in environmental waters. Spray-coating and dip coating methodologies were used to coat the surfaces of six stainless steel bolts with a layer of HLB/PAN particles, which served as the extractive substrate in the proposed device. In addition, this sampler was designed to withstand rough handling, long storage times, and various environmental conditions.

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A novel hydrophilic-lipophilic balanced (HLB) thin film solid-phase microextraction (TF-SPME) device is proposed for polarity-balanced determinations of volatile organic compounds. The proposed HLB particles used in the preparation of these membranes were prepared using a precipitation polymerization technique and determined to have a specific surface area of 335 m/g with an average pore diameter of 13 Å. Membranes prepared from these particles were found to extract 1.

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The aim of the current study is the establishment of Green Analytical Chemistry strategies for water analysis by elimination/reduction of hazardous chemicals, energy consumption, and waste generation throughout the entire analytical workflow. The first approach introduced in this manuscript consists of addition of water to a sampling vessel that contains a thin film microextraction (TFME) device, followed by removal of the device after equilibration, and subsequent quantification of the extracted components by thermal desorption GC/MS. In this approach, namely the in-bottle TFME approach, analyte-loss associated errors that stem from analyte adherence to glass surfaces and/or degradation are avoided as extraction occurs in situ, while analytes are isolated from a complex matrix that contains degradation agents (bacteria, oxidizing or reducing species, etc.

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To date, solid-phase microextraction (SPME) fibers used for in vivo bioanalysis can be too fragile and flexible, which limits suitability for direct tissue sampling. As a result, these devices often require a sheathing needle to prepuncture robust sample matrixes and protect the extraction phase from mechanical damage. To address this limitation, a new SPME device is herein presented which incorporates an extraction phase recessed into the body of a solid needle.

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The primary goal of the present study is the inter-laboratory evaluation of a thin film microextraction (TFME) technique to be used as an alternative approach to liquid-liquid extraction (LLE). Polydimethylsiloxane/divinylbenzene (PDMS/DVB) and PDMS/DVB-carbon mesh supported membranes were used for the extraction of 23 targeted pesticides, while a thermal desorption unit (TDU) was employed to transfer these analytes to a GC/MS instrument for separation and detection. After optimization of the most critical parameters, both membranes were capable of achieving limits of detection (LOD) in the low ng L range while demonstrating excellent robustness, withstanding up to 100 extractions/desorption cycles.

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Article Synopsis
  • Solid phase microextraction (SPME) on-fiber derivatization methods improve detection limits and analysis of unstable substances while minimizing solvent use; however, previous methods faced issues with reproducibility and toxic reagents.
  • A new reusable standard gas generating vial containing pentafluorophenyl hydrazine (PFPH) enables consistent loading of the derivatization reagent, demonstrating strong reproducibility and stability over extended periods.
  • This development has potential applications in monitoring volatile compounds like aldehydes in various contexts, including food spoilage and environmental analysis, marking it as a significant advancement in handling reactive and unstable standards.
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In this work, a durable and easy to handle thin film microextraction (TFME) device is reported. The membrane is comprised of poly(divinylbenzene) (DVB) resin particles suspended in a high-density polydimethylsiloxane (PDMS) glue, which is spread onto a carbon fiber mesh. The currently presented membrane was shown to exhibit a substantially lesser amount of siloxane bleed during thermal desorption, while providing a statistically similar extraction efficiency toward a broad spectrum of analytes varying in polarity when compared to an unsupported DVB/PDMS membrane of similar shape and size which was prepared with previously published methods.

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In this work, a highly reproducible standard gas generating vial is proposed. The vial is comprised of a silicon diffusion pump oil spiked with an appropriate calibration compound, such as modified McReynolds probes (benzene, 2-pentanone, pyridine, 1-nitropropane, 1-pentanol, and n-octane), and then mixed with polystyrene/divinylbenzene (PS/DVB) particles. The concentrations of these compounds in gaseous headspace were found to substantially decrease in comparison to previously developed hydrocarbon pump oil based vials; hence, the amount of standard loaded onto SPME fibers was at most, half that of the previous vial design.

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