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Zheng Ouyang – One of the best experts on this subject based on the ideXlab platform.

  • Fast screening of prohibited chemicals in plastic toys using Ambient Ionization mass spectrometry
    International Journal of Mass Spectrometry, 2019
    Co-Authors: Simin Cheng, Wenbo Cao, Xu Zhao, Zheng Ouyang

    Abstract In this work, we developed methods for rapid analysis of prohibited chemicals in trade products, e.g. plastic toys for children. Two Ambient Ionization methods, zero-voltage paper spray Ionization (zvPSI) and transmission low-temperature plasma (T-LTP) probe, were used to enable the direct detection of a broad range of prohibited substances, including plasticizers, disperse dyestuffs, and aromatic amines. The limits of detection (LODs) achieved for plasticizers and disperse dyestuffs/aromatic amines were 0.080–3.9 ng and 0.024–0.77 ng, respectively. Extremely simple sampling process was involved by surface chemical extraction using organic solvents. The developed methods were applied for detecting prohibited harmful chemicals in 12 plastic toy samples, among which four were detected with di(2-ethyl)hexyl phthalate, a commonly used plasticizer. The total time of the entire analysis process for each sample was less than 3 min, from sampling to final mass spectrometry (MS) analysis, making the methodology suitable for real-time analysis. The developed method could potentially be implemented for rapid pre-screening of trade products at the customs, especially when coupled with a miniature mass spectrometer.

  • Rapid identification of regulated organic chemical compounds in toys using Ambient Ionization and a miniature mass spectrometry system.
    Talanta, 2017
    Co-Authors: Guo Xiangyu, Hua Bai, Yue Ren, Zheng Ouyang

    Abstract Rapid, on-site analysis was achieved through significantly simplified operation procedures for a wide variety of toy samples (crayon, temporary tattoo sticker, finger paint, modeling clay, and bubble solution) using a miniature mass spectrometry system with Ambient Ionization capability. The labor-intensive analytical protocols involving sample workup and chemical separation, traditionally required for MS-based analysis, were replaced by direct sampling analysis using Ambient Ionization methods. A Mini β ion trap miniature mass spectrometer was coupled with versatile Ambient Ionization methods, e.g. paper spray, extraction spray and slug-flow microextraction nanoESI for direct identification of prohibited colorants, carcinogenic primary aromatic amines, allergenic fragrances, preservatives and plasticizers from raw toy samples. The use of paper substrates coated with Co3O4 nanoparticles allowed a great increase in sensitivity for paper spray. Limits of detection as low as 5 μg kg-1 were obtained for target analytes. The methods being developed based on the integration of Ambient Ionization with miniature mass spectrometer represent alternatives to current in-lab MS analysis operation, and would enable fast, outside-the-lab screening of toy products to ensure children’s safety and health.

  • Ambient Ionization and Miniature Mass Spectrometry Systems for Disease Diagnosis and Therapeutic Monitoring.
    Theranostics, 2017
    Co-Authors: Wenpeng Zhang, Xiao Wang, Yu Xia, Zheng Ouyang

    Mass spectrometry has become a powerful tool in the field of biomedicine. The combination of Ambient Ionization and miniature mass spectrometry systems could most likely fulfill a significant need in medical diagnostics, providing highly specific molecular information in real time for clinical and even point-of-care analysis. In this review, we discuss the recent development of Ambient Ionization and miniature mass spectrometers as well as their potential in disease diagnosis and therapeutic monitoring, with an emphasis on their capability in analysis of biofluids and tissues. We also speculate the future development of the integrated, miniature MS systems and provide our perspectives on the challenges in technical development as well as possible solutions for path forward.

R. Graham Cooks – One of the best experts on this subject based on the ideXlab platform.

  • Fatty Acid Patterns Detected By Ambient Ionization Mass Spectrometry in Canine Invasive Urothelial Carcinoma From Dogs of Different Breeds.
    Bladder cancer (Amsterdam Netherlands), 2018
    Co-Authors: Cedric D'hue, Alan K. Jarmusch, Deepika Dhawan, Tyler Peat, José A. Ramos-vara, Deborah W. Knapp, R. Graham Cooks

    Background In early work Ambient Ionization mass spectrometry (MS) revealed lipid patterns distinguishing muscle invasive bladder cancer (invasive urothelial carcinoma, InvUC) from normal urothelium. A new Ambient Ionization MS approach, touch spray MS (TS-MS) can rapidly generate mass spectra in real time, potentially in a point-of-care setting. A tissue sample removed from a patient is touched by a probe, and mass spectra generated within seconds. Objective To validate TS-MS methods using specimens from naturally-occurring InvUC in dogs where the cancer closely mimics the human condition, and to demonstrate proof-of-concept that TS-MS can elucidate lipid patterns distinguishing InvUC from normal urothelium. Methods Samples of normal urothelium and InvUC from dogs of several breeds were analyzed by TS-MS with correlative histopathology across each sample. Results were compared to those obtained with desorption electrospray Ionization mass spectrometry (DESI-MS), a more traditional method. Data were analyzed by Principal CompComponent Analysis and Linear Discriminant Analysis. Results Lipid patterns identified by TS-MS, as well as by DESI-MS, differed between InvUC and normal urothelium with m/z 281.5 (oleic acid) and m/z 563.5 (oleic acid dimer) substantially contributing to the differences. Using histologic diagnosis as the gold standard, TS-MS had a global prediction rate of 93%. Conclusions TS-MS can be used to identify lipid patterns that differentiate canine InvUC from normal urothelium. Optimization of TS-MS could lead to a point-of-care approach to distinguish cancer from normal in ex vivo tissues in real time, and to define biochemical processes leading to cancer development and progression.

  • From DESI to the MasSpec Pen: Ambient Ionization Mass Spectrometry for Tissue Analysis and Intrasurgical Cancer Diagnosis.
    Clinical chemistry, 2018
    Co-Authors: Hannah Marie Brown, Valentina Pirro, R. Graham Cooks

    With the increasing prevalence of cancer, there is strong motivation to accurately assess and diagnose tissue during cancer surgery. Assessment of the negative margin for the maximum possible tumor excision is critical for achieving remission and improving overall patient survival. To that end, the MasSpec Pen is the latest iteration of Ambient Ionization mass spectrometry (MS)3 for the purposes of tissue diagnosis that allows direct, real-time tissue sampling and molecular analysis (1). This development occurs at a time when molecular analysis is rapidly emerging as an important aspect of cancer tissue diagnosis and substantial efforts are made to develop technology that is automated, biocompatible, nondestructive, handheld, and available at the bedside. While the gold standard for cancer diagnosis continues to be histopathology augmented by immunohistochemistry, molecular analysis holds great promise for several reasons: ( a ) small molecules provide information on the phenotype that may be unavailable from examination of the genotype; ( b ) complex and dynamic interactions between biomolecules influence biological functions and so signify the health state of an entity; and ( c ) rapid and accurate pattern recognition of tissue types is possible with multiple spectroscopic/spectrometric methods. With pathology providing a gold standard reference, it has become clear that both MS and Raman specspectroscopy have potential value for cancer diagnostics. A minimum requirement for surgical relevance is that a technique provides reliable molecular data very rapidly while using unprocessed samples. Ambient Ionization MS is a suite of methods that does exactly that, allowing chemical information to be obtained for a variety of analytes at atmospheric pressure, thereby eliminating the usual requirement for Ionization to be performed under suction or for prior sample purification and pretreatment. The first tissue measurements completed with Ambient Ionization, reported in 2005, were based on phospholipid distributions, and they served to demarcate tissue type and disease state. …

  • Ambient Ionization Mass Spectrometry Measurement of Aminotransferase Activity.
    Journal of the American Society for Mass Spectrometry, 2017
    Co-Authors: Xin Yan, Chengsen Zhang, R. Graham Cooks

    A change in enzyme activity has been used as a clinical biomarker for diagnosis and is useful in evaluating patient prognosis. Current laboratory measurements of enzyme activity involve multi-step derivatization of the reaction products followed by quantitative analysis of these derivatives. This study simplified the reaction systems by using only the target enzymatic reaction and directly detecting its product. A protocol using paper spray mass spectrometry for identifying and quantifying the reaction product has been developed. Evaluation of the activity of aspartate aminotransferase (AST) was chosen as a proof-of-principle. The volume of sample needed is greatly reduced compared with the traditional method. Paper spray has a desalting effect that avoids sprayer clogging problems seen when examining serum samples by nanoESI. This very simple method does not require sample pretreatment and additional derivatization reactions, yet it gives high quality kinetic data, excellent limits of detection (60 ppb from serum), and coefficients of variation

Graham R Cooks – One of the best experts on this subject based on the ideXlab platform.

  • raman spectroscopy coupled with Ambient Ionization mass spectrometry a forensic laboratory investigation into rapid and simple dual instrumental analysis techniques
    International Journal of Mass Spectrometry, 2020
    Co-Authors: Nicolas M Morato, Patrick W. Fedick, Graham R Cooks

    Abstract We present a laboratory experiment, developed around a pair of instrumental analysis techniques, Raman specspectroscopy and Ambient Ionization mass spectrometry (MS), conducted by senior chemistry undergraduate students for bulk analysis of over-the-counter drugs using benchtop versions of the two instruments, as well as trace analysis of illicit drugs utilizing the corresponding portable instruments. The identification and confirmation of seized drugs is a routine operation in forensic laboratories that can be simplified using these two instrumental techniques in tandem. Bulk samples are readily analyzed using conventional Raman specspectroscopy followed by paper cone spray Ionization (PCSI) MS, while trace analysis is allowed by a simple single-substrate dual-analyzer method using surface enhanced Raman specspectroscopy (SERS) from paper followed by paper spray Ionization (PSI) MS. The introduction of these novel strategies to the students exposed them to potential career paths in forensic science by means of a hands-on experience that provided fundamental knowledge about this set of analytical methods, including intercomparisons of their performance, as well as practical issues like costs, regulations and databases. The use of portable instrumentation represents an additional learning experience for the students, considering that it is cutting-edge technology that is just now being transferred from academic to industrial labs and that it allows a valuable discussion of the advantages and disadvantages of bringing the laboratory to the field.

  • Ambient Ionization mass spectrometric analysis of human surgical specimens to distinguish renal cell carcinoma from healthy renal tissue
    Analytical and Bioanalytical Chemistry, 2016
    Co-Authors: Clint M Alfaro, Alan K. Jarmusch, Valentina Pirro, Liang Cheng, Timothy A. Masterson, Kevin S Kerian, Graham R Cooks

    Touch spray-mass spectrometry (TS-MS) is an Ambient Ionization technique (Ionization of unprocessed samples in the open air) that may find intraoperative applications in quickly identifying the disease state of cancerous tissues and in defining surgical margins. In this study, TS-MS was performed on fresh kidney tissue (∼1–5 cm3), within 1 h of resection, from 21 human subjects afflicted by renal cell carcinoma (RCC). The preliminary diagnostic value of TS-MS data taken from freshly resected tissue was evaluated. Principal compcomponent analysis (PCA) of the negative ion mode (m/z 700–1000) data provided the separation between RCC (16 samples) and healthy renal tissue (13 samples). Linear discriminant analysis (LDA) on the PCA-compressed data estimated sensitivity (true positive rate) and specificity (true negative rate) of 98 and 95 %, respectively, based on histopathological evaluation. The results indicate that TS-MS might provide rapid diagnostic information in spite of the complexity of unprocessed kidney tissue and the presence of interferences such as urine and blood. Desorption electrospray Ionization-MS imaging (DESI-MSI) in the negative Ionization mode was performed on the tissue specimens after TS-MS analysis as a reference method. The DESI imaging experiments provided phospholipid profiles (m/z 700–1000) that also separated RCC and healthy tissue in the PCA space, with PCA-LDA sensitivity and specificity of 100 and 89 %, respectively. The TS and DESI loading plots indicated that different ions contributed most to the separation of RCC from healthy renal tissue (m/z 794 [PC 34:1 + Cl]− and 844 [PC 38:4 + Cl]− for TS vs. m/z 788 [PS 36:1 − H]− and 810 [PS 38:4 − H]− for DESI), while m/z 885 ([PI 38:4 − H]−) was important in both TS and DESI. The prospect, remaining hurdles, and future work required for translating TS-MS into a method of intraoperative tissue diagnosis are discussed.

  • rapid analysis of synthetic cannabinoids using a miniature mass spectrometer with Ambient Ionization capability
    Talanta, 2015
    Co-Authors: Wentao Li, Graham R Cooks, Chao Wang, Zheng Ouyang

    Synthetic cannabinoids are an emerging class of drugs of abuse and are of a great concern for transport control and usage regulation. In this study, we have developed rapid analytical methods using a miniature mass spectrometer for the identification of synthetic cannabinoids, as the traces of bulk powders on surfaces or substances in blood and urine. Significantly simplified work flows were developed by employing two Ambient Ionization methods, the paper spray and extraction spray Ionization. Using five synthetic cannabinoids as examples, a limit of detection of 2 ng was estimated for the detection of trace powders on a bench surface and limits of quantitation as good as 10 ng/mL were obtained for the analysis of blood and urine samples.

Joshua S. Wiley – One of the best experts on this subject based on the ideXlab platform.

  • Mass spectrometry in the home and garden
    Journal of the American Society for Mass Spectrometry, 2015
    Co-Authors: Christopher J. Pulliam, Ryan M. Bain, Joshua S. Wiley, Zheng Ouyang, R. Graham Cooks

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external Ambient Ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the Ambient Ionization methods of paper spray, leaf spray, and low temperature plasma Ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application.

  • handheld low temperature plasma probe for portable point and shoot Ambient Ionization mass spectrometry
    Analytical Chemistry, 2013
    Co-Authors: Joshua S. Wiley, Jacob T. Shelley, Graham R Cooks

    We describe a handheld, wireless low-temperature plasma (LTP) Ambient Ionization source and its performance on a benchtop and a miniature mass spectrometer. The source, which is inexpensive to build and operate, is battery-powered and utilizes miniature helium cylinders or air as the discharge gas. Comparison of a conventional, large-scale LTP source against the handheld LTP source, which uses less helium and power than the large-scale version, revealed that the handheld source had similar or slightly better analytical performance. Another advantage of the handheld LTP source is the ability to quickly interrogate a gaseous, liquid, or solid sample without requiring any setup time. A small, 7.4-V Li-polymer battery is able to sustain plasma for 2 h continuously, while the miniature helium cylinder supplies gas flow for approximately 8 continuous hours. Long-distance ion transfer was achieved for distances up to 1 m.

  • in situ analysis of agrochemical residues on fruit using Ambient Ionization on a handheld mass spectrometer
    Analyst, 2011
    Co-Authors: Santosh Soparawalla, Joshua S. Wiley, Zheng Ouyang, Fatkhulla K Tadjimukhamedov, Graham R Cooks

    We describe a rapid in situ method for detecting agrochemicals on the surface or in the tissue of fruit using a portable mass spectrometer equipped with an Ambient Ionization source. Two such Ionization methods, low temperature plasma (LTP) and paper spray (PS), were employed in experiments performed at a local grocery store. LTP was used to detect diphenylamine (DPA) directly from the skin of apples in the store and those treated after harvest with DPA were recognized by MS and MS/MS. These data therefore allowed ready distinction between organic and non-organic apples. DPA was also found within the internal tissue of purchased apples and its distribution was mapped using LTP. Similarly, thiabendazole residues were detected on the skin of treated oranges in a grocery store experiment in which paper spray was performed by wiping the orange surface with a moist commercial lens wipe and then applying a high voltage to ionize the chemicals directly from the wipe. The handheld mass spectrometer used in these measurements is capable of performing several stages of tandem mass spectrometry (up to MS5); the compounds on the fruit were identified by their MS/MS fragmentation patterns. Protonated DPA (m/z 170) produced a characteristic MS2 fragment ion at m/z 92, while thiabendazole was identified by MS3 using precursor to fragment ion transitions m/z 202 → m/z 175 →m/z 131. These particular examples exemplify the power of in situ analysis of complex samples using Ambient Ionization and handheld mass spectrometers.

Juan F. García-reyes – One of the best experts on this subject based on the ideXlab platform.

  • Direct olive oil analysis by mass spectrometry: A comparison of different Ambient Ionization methods.
    Talanta, 2017
    Co-Authors: Felipe J. Lara-ortega, Juan F. García-reyes, Miriam Beneito-cambra, José Robles-molina, Bienvenida Gilbert-lópez, Antonio Molina-díaz

    Abstract Analytical methods based on Ambient Ionization mass spectrometry (AIMS) combine the classic outstanding performance of mass spectrometry in terms of sensitivity and selectivity along with convenient features related to the lack of sample workup required. In this work, the performance of different mass spectrometry-based methods has been assessed for the direct analyses of virgin olive oil for quality purposes. Two sets of experiments have been setup: (1) direct analysis of untreated olive oil using AIMS methods such as Low-Temperature Plasma Mass Spectrometry (LTP-MS) or paper spray mass spectrometry (PS-MS); or alternatively (2) the use of atmospheric pressure Ionization (API) mass spectrometry by direct infusion of a diluted sample through either atmospheric pressure chemical Ionization (APCI) or electrospray (ESI) Ionization sources. The second strategy involved a minimum sample work-up consisting of a simple olive oil dilution (from 1:10 to 1:1000) with appropriate solvents, which originated critical carry over effects in ESI, making unreliable its use in routine; thus, ESI required the use of a liquid-liquid extraction to shift the measurement towards a specific part of the composition of the edible oil (i.e. polyphenol rich fraction or lipid/fatty acid profile). On the other hand, LTP-MS enabled direct undiluted mass analysis of olive oil. The use of PS-MS provided additional advantages such as an extended Ionization coverage/molecular weight range (compared to LTP-MS) and the possibility to increase the Ionization efficiency towards nonpolar compounds such as squalene through the formation of Ag+ adducts with carbon-carbon double bounds, an attractive feature to discriminate between oils with different degree of unsaturation.

  • Rapid determination of multiclass fungicides in wine by low-temperature plasma (LTP) Ambient Ionization mass spectrometry
    Analytical Methods, 2015
    Co-Authors: Miriam Beneito-cambra, Antonio Molina-díaz, Patricia Pérez-ortega, Juan F. García-reyes

    A low-temperature plasma (LTP) probe is a plasma-based technique that permits the direct and rapid Ambient Ionization and mass analysis of relatively complex samples in their native environment. It belongs to the Ambient desorption/Ionization mass spectrometry (MS) technique, and these features map well against the requirements of food quality and safety testing. In this study, the application of LTP-MS for the rapid screening and detection of pesticides in wines has been evaluated. Aliquots of a sample extract (3 μL of each solution) were deposited on a heated (120 °C) microscope glass slide for LTP-MS analysis. The analytical performance of LTP-MS has been studied for a set of 10 multiclass fungicides selected according to their relevance and presence in actual wine samples. The compounds included in the study were azoxystrobin, carbendazim, dimethomorph, fenhexamid, flusilazol, metalaxyl, penconazole, tebuconazole, imazalil and thiabendazole. Two different approaches were examined: (i) the direct analyses of wines with no prior treatment besides a simple sample dilution, and (ii) the analyses of sample extracts obtained after a thorough sample preparation step using solid-phase extraction with polymeric cartridges. The proposed approach enabled the detection of the pesticides in wine at low concentration levels in the range from 15 μg L−1 to 300 μg L−1 (fulfilling maximum residue levels (MRLs) set in EU regulations in all cases) by means of tandem mass spectrometry experiments with an ion trap operated in the positive Ionization mode. The qualitative results obtained with actual red wine market samples compared well against the reference method based on liquid chrochromatography/mass spectrometry. Various examples shown demonstrate that Ambient LTP-MS can be applied for the detection of these chemicals in beverages without sample treatment steps besides dilution.

  • Screening of agrochemicals in foodstuffs using low-temperature plasma (LTP) Ambient Ionization mass spectrometry
    The Analyst, 2010
    Co-Authors: Joshua S. Wiley, Zheng Ouyang, Juan F. García-reyes, Jason D. Harper, Nicholas A. Charipar, R. Graham Cooks

    Low-temperature plasma (LTP) permits direct Ambient Ionization and mass analysis of samples in their native environment with minimal or no prior preparation. LTP utilizes dielectric barrier discharges (DBDs) to create a low power plasma which is guided by gas flow onto the sample from which analytes are desorbed and ionized. In this study, the potential of LTP-MS for the detection of pesticide residues in food is demonstrated. Thirteen multi-class agricultural chemicals were studied (ametryn, amitraz, atrazine, buprofezin, DEET, diphenylamine, ethoxyquin, imazalil, isofenphos-methyl, isoproturon, malathion, parathionethyl and terbuthylazine). To evaluate the potential of the proposed approach, LTP-MS experiments were performed directly on fruit peels as well as on fruit/vegetable extracts. Most of the agrochemicals examined displayed remarkable sensitivity in the positive ion mode, giving limits of detection (LOD) for the direct measurement in the low picogram range. Tandem mass spectrometry (MS/MS) was used to confirm identification of selected pesticides by using for these experiments spiked fruit/vegetable extracts (QuEChERS, a standard sample treatment protocol) at levels as low as 1 pg, absolute, for some of the analytes. Comparisons of the data obtained by direct LTP-MS were made with the slower but more accurate conventional LC-MS/MS procedure. Herbicides spiked in aqueous solutions were detectable at LODs as low as 0.5 µg L−1 without the need for any sample preparation. The results demonstrate that Ambient LTP-MS can be applied for the detection and confirmation of traces of agrochemicals in actual market-purchased produce and in natural water samples. Quantitative analysis was also performed in a few selected cases and displayed a relatively high degree of linearity over four orders of magnitude.