The aroma profile is an important marker for wine quality. Various classes of compounds are responsible for the aroma of wine, and one such class is terpenoids. In the context of this work, a ...validated gas chromatography-mass spectrometry (GC-MS) method for the quantitation of terpenoids in red and white wine using headspace solid-phase microextraction (HS-SPME) and solid-phase extraction (SPE) was established. Calibrations were performed in the respective base wine using both sample preparation methods. The linearity, precision and accuracy evaluated for the respective matrices were excellent for both sample preparations. However, the HS-SPME approach was more sensitive and more accurate. For both sample preparations, the quantification limits were lower than the odor thresholds in wine. The terpenoid concentrations (µg/L) were evaluated for 13 white wines using both sample preparation methods. Importantly, the online HS-SPME approach was more sensitive than the offline SPE method. The major terpenoids identified in the white wines evaluated were linalool (0.2-63 µg/L), geraniol (nd-66 µg/L) and α-terpineol (nd-85 µg/L).
Recent progress in metabolomics and the development of increasingly sensitive analytical techniques have renewed interest in global profiling, i.e., semiquantitative monitoring of all chemical ...constituents of biological fluids. In this work, we have performed global profiling of NIST SRM 1950, “Metabolites in Human Plasma”, using GC-MS, LC-MS, and NMR. Metabolome coverage, difficulties, and reproducibility of the experiments on each platform are discussed. A total of 353 metabolites have been identified in this material. GC-MS provides 65 unique identifications, and most of the identifications from NMR overlap with the LC-MS identifications, except for some small sugars that are not directly found by LC-MS. Also, repeatability and intermediate precision analyses show that the SRM 1950 profiling is reproducible enough to consider this material as a good choice to distinguish between analytical and biological variability. Clinical laboratory data shows that most results are within the reference ranges for each assay. In-house computational tools have been developed or modified for MS data processing and interactive web display. All data and programs are freely available online at http://peptide.nist.gov/ and http://srmd.nist.gov/.
Tea is the second most consumed beverage, and its aroma, determined by volatile compounds (VOCs) present in leaves or developed during the processing stages, has a great influence on the final ...quality. The goal of this study is to determine the volatilome of different types of tea to provide a competitive tool in terms of time and costs to recognize and enhance the quality of the product in the food chain. Analyzed samples are representative of the three major types of tea: black, green, and white. VOCs were studied in parallel with different technologies and methods: gas chromatography coupled with mass spectrometer and solid phase microextraction (SPME-GC-MS) and a device called small sensor system, (S3). S3 is made up of tailor-made metal oxide gas sensors, whose operating principle is based on the variation of sensor resistance based on volatiloma exposure. The data obtained were processed through multivariate statistics, showing the full file of the pre-established aim. From the results obtained, it is understood how supportive an innovative technology can be, remotely controllable supported by machine learning (IoF), aimed in the future at increasing food safety along the entire production chain, as an early warning system for possible microbiological or chemical contamination.
Real-time online monitoring of volatile organic compounds (VOCs) in ambient air is crucial for timely and effective human health protection. Here, we developed an innovative, automated two-staged ...adsorption/thermal desorption gas chromatography/mass spectrometry (GC/MS) system for real-time online monitoring of 117 regulated volatile organic compounds (VOCs). This system comprised a sampling unit, water management trap, two-staged adsorption/thermal desorption unit, thermoelectric coolers (TECs), and a commercial GC/MS system. By implementing a micro-purge-and-trap (MP & T) step and a two-staged adsorption/thermal desorption unit, the presence of interfering substances was effectively minimized. The utilization of a heart-cutting GC, combined with a single MS detector, facilitated the precise separation and detection of 117 C
2
–C
12
VOCs, while circumventing the identification and coelution challenges commonly associated with traditional GC-FID or GC-FID/MS methods. The performance of our newly developed online system was meticulously optimized and evaluated using standard gas mixtures. Under optimal conditions, we achieved impressive results, with
R
2
values ≥ 0.9946 for the standard linear curves of all 117 VOCs, demonstrating a precision (RSD) ranging from 0.2% to 6.4%. When applied in the field monitoring, the concentration drifts for 10 ppbv standard gas mixtures were 0.01–5.64% within 24 h. Our study developed a system for online monitoring of 117 atmospheric VOCs with relatively high accuracy and robustness.
We developed the WRF-GC model, an online coupling of the Weather Research and Forecasting (WRF) mesoscale meteorological model and the GEOS-Chem atmospheric chemistry model, for regional atmospheric ...chemistry and air quality modeling. WRF and GEOS-Chem are both open-source community models.
WRF-GC offers regional modellers access to the latest GEOS-Chem chemical module, which is state of the science, well documented, traceable, benchmarked, actively developed by a large international user base, and centrally managed by a dedicated support team. At the same time, WRF-GC enables GEOS-Chem users to perform high-resolution forecasts and hindcasts for any region and time of interest. WRF-GC uses unmodified copies of WRF and GEOS-Chem from their respective sources; the coupling structure allows future versions of either one of the two parent models to be integrated into WRF-GC with relative ease. Within WRF-GC, the physical and chemical state variables are managed in distributed memory and translated between WRF and GEOS-Chem by the WRF-GC coupler at runtime. We used the WRF-GC model to simulate surface PM2.5 concentrations over China during 22 to 27 January 2015 and compared the results to surface observations and the outcomes from a GEOS-Chem Classic nested-China simulation. Both models were able to reproduce the observed spatiotemporal variations of regional PM2.5, but the WRF-GC model (r=0.68, bias =29 %) reproduced the observed daily PM2.5 concentrations over eastern China better than the GEOS-Chem Classic model did (r=0.72, bias =55 %). This was because the WRF-GC simulation, nudged with surface and upper-level meteorological observations, was able to better represent the pollution meteorology during the study period.
The WRF-GC model is parallelized across computational cores and scales well on massively parallel architectures. In our tests where the two models were similarly configured, the WRF-GC simulation was 3 times more efficient than the GEOS-Chem Classic nested-grid simulation due to the efficient transport algorithm and the Message Passing Interface (MPI)-based parallelization provided by the WRF software framework. WRF-GC v1.0 supports one-way coupling only, using WRF-simulated meteorological fields to drive GEOS-Chem with no chemical feedbacks. The development of two-way coupling capabilities, i.e., the ability to simulate radiative and microphysical feedbacks of chemistry to meteorology, is under way. The WRF-GC model is open source and freely available from http://wrf.geos-chem.org (last access: 10 July 2020).
The market of falsified or sub-standard medical products is a global scale phenomenon. This issue affects a wide range of medications, including life-saving medical products. In high-income countries ...the most falsified products are those defined “lifestyle”, which include foremost anabolic steroids and phosphodiesterase 5 inhibitors. The spread of these products in the last years has been possible also because of their online purchase, since they can be bought anonymously and without any medical supervision or prescription. Their use can pose a serious threat for public health, especially because often are manufactured without adherence to quality standards. This leads to final products containing active ingredients different from those declared, at the wrong or unknown dose and contaminated with metals, synthesis by-products and other chemical substances. In this work, we present results on characterisation of illegal pharmaceutical products and doping agents by combining different techniques: chromatography coupled to mass spectrometry for organic analysis and accelerator-based nuclear analytical techniques, such as ion beam analysis (IBA), for elemental analysis. Three IBA techniques, namely PIXE (particle induced X-ray emission), PIGE (particle induced gamma-ray emission) and EBS (elastic backscattering spectrometry) were used in external beam mode to provide an elemental characterisation of the as-is material, placed simply in front of the proton beam, thus avoiding the need of preparing them with pre-analytical steps and greatly enhancing the measurement throughput. Several elements (F, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Br and Sr) were identified in the analysed products. External beam IBA measurements provided the quantitative elemental characterisation of the illegal pharmaceutical products and doping agents under study, complementary to the organic analysis results by chromatography and mass spectrometry thus allowing a rapid (a few minutes) and non-destructive direct assessment of the material for forensic purposes. For the first time IBA results from doping products are reported and further analysis by IBA involving two different accelerator laboratories (one in Italy and one in Brazil) allowed the comparison of results obtained on the same pharmaceutical product. Starting from the results obtained in our study, the actualisation of new research plans should be evaluated, which could lay the foundation for a classification system of illegal pharmaceutical products, doping products. and other substances, based on chromatography, mass spectrometry and IBA measurements; this could allow drawing inferences about the common characteristics of these substances, e.g. provenience of bulk materials, site of production etc. With this purpose, results obtained from two samples of the same pharmaceutical product by IBA in two different accelerator laboratories (one in Italy and one in Brazil) are compared.
•IBA results from doping products are reported for the first time.•IBA methods combined with GC-MS and HPLC-HRMS were used to study illegal pharmaceutical products.•External beam IBA provided the concentrations of several elements in tablets without any sample preparation.•GC-MS and HPLC-HRMS provide the characterisation of the active compounds and of organic by-products.•IBA results obtained in two laboratories were compared, confirming some criteria for detecting illegal medicines.
Novel synthetic opioids (NSOs) are a class of opioid agonists that include analogs of fentanyl and structurally distinct non-fentanyl compounds normally used as standalone products, heroin ...adulterants, or constituents of counterfeit pain pills. Most NSOs are not currently scheduled in the U.S., are predominantly illegally synthesized, and sold on the Darknet. Among them, the cinnamylpiperazine derivatives such as bucinnazine (AP-237), AP-238, and 2-methyl-AP-237 and the arylcyclohexylamine derivatives, analogs of ketamine, such as 2-fluoro-deschloroketamine (2 F-DCK) have appeared in several monitoring systems. Two white powders purchased on the internet as bucinnazine were first analyzed with polarized light microscopy followed by direct analysis in real time-mass spectrometry (DART-MS) and gas chromatography-mass spectrometry (GC-MS). Both powders were white crystals with no other significant microscopic properties. The DART-MS analysis showed the presence of 2-fluorodeschloroketamine in powder #1, and AP-238 in powder #2. Identification was confirmed by GC-MS. The purity of each substance was 78.0% for powder #1, and 88.9% for powder #2, respectively. The toxicological risk associated with the misuse of NSOs still needs further study. The absence of bucinnazine and the presence of different active compounds in internet purchased samples raises public health and safety concerns.
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•Powder samples advertised online as AP-237 were identified as 2 F-DCK and AP-238.•Found substances lack toxicity data increasing the risk of buying products online.•Lack of information on the identity of products can lead to toxicity and overdose.
We present an automatically and autonomously operating online laboratory equipped with laboratory chromatographs as an example of Analytics 4.0. At BASF’s largest production site in Ludwigshafen, ...Germany, multiple GC, HPLC, and IC systems are used in a mostly unstaffed laboratory for automated wastewater monitoring. The purpose of the online system is to prevent unwanted discharges of organic compounds into the wastewater treatment plant and thus protection of the river Rhine. By use of different chromatography and sample preparation techniques, a wide spectrum of compounds can be quantitatively assessed. Most analyzers are coupled to mass spectrometers, and all are equipped with robotic autosamplers. Mixed wastewater samples are collected automatically at 20-min intervals and distributed to the instruments. To operate the online system 24/7, sensors, visualization tools, special software packages, remote access tools, and other assistance systems are required. Many of the software features are as yet not commercially available and thus had to be developed and programmed in-house since they are required in an Analytics 4.0 environment.
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