Overlooked Trace Molecules in Organic Aerosol Revealed by Gas Chromatography-Orbitrap Mass Spectrometry.

Molecular characterization of organic aerosol (OA) is crucial for understanding its sources and atmospheric processes. However, the chemical components of OA remain not well constrained. This study used gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap MS) and GC-Quadrupole MS (GC-qMS) to investigate the organic composition in PM2.5 from Xi'an, Northwest China. GC-Orbitrap MS identified 335 organic tracers, including overlooked isomers and low-concentration molecules, approximately 1.6 times more than GC-qMS. The "molecular corridor" assessment shows the superior capability of GC-Orbitrap MS in identifying an expansive range of compounds with higher volatility and oxidation states, such as furanoses/pyranoses, di/hydroxy/ketonic acids, di/poly alcohols, aldehydes/ketones, and amines/amides. Seasonal variations in OA composition reflect diverse sources: increased di/poly alcohols in winter are derived from indoor emissions, furanoses/pyranoses and heterocyclics in spring and summer might be from biogenic emissions and secondary formation, and amides in autumn are probably from biomass burning. Integrating partial least squares discriminant analysis (PLS-DA) and potential source contribution function (PSCF) models, the source similarities and differences are further elucidated, highlighting the role of local emissions and transport from southern cities. This study offers new insights into the OA composition aided by the high mass resolution and sensitivity of GC-Orbitrap MS.

Determination of subpicogram levels of airborne polycyclic aromatic hydrocarbons for personal exposure monitoring assessment.

A method based on the use of GC coupled to Q-exactive Orbitrap mass spectrometry (GC-Orbitrap-MS) has been developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) at sub-picogram levels. Outdoor ambient air particulate matter (PM2.5) and standard reference materials (SRM2260a) were analyzed in full scan mode showing low instrumental uncertainties (1-22%) and high linearity over a wide concentration range (0.5 pg and 500 pg/µL). Good reproducibility was obtained compared to the use of conventional single quadrupole GC-MS of PM samples. The quantification limit of the GC-Orbitrap-MS method for full scan analysis of PAHs in outdoor ambient air PM samples was 0.5 pg/µL. This low limit allowed the analysis of PAHs in samples collected with low volumes (< 0.5 m3), such as punch samples from whole filters or filter strips from personal exposure monitoring equipment. PAHs were successfully analyzed in filter strips from real-time Aethalometer AE51 equivalent black carbon (eBC) analyzers used in urban and rural sites, and in personal exposure monitors of firefighters during prescribed burns. The correlations between PAHs and eBC in these analyses were very strong (r2 ≥ 0.93). However, the equations obtained reflected the dominance of different emission sources, such as traffic in urban areas, wood burning for domestic heating, or wildfires. The method reported here affords the analyses of PAHs in high precision studies of atmospheric PM samples, e.g., high frequency sampling of low volumes, affording personal exposure monitoring assessments.

Non-targeted identification and risk assessment of unknown substances in disposable plastic tableware by GC-Orbitrap HRMS.

Disposable plastic tableware was widely used and it was particularly important to identify potential hazardous substances in it and evaluate the risk to humans health. In this study, 85 substances were identified in 60 samples (22 bowls, 20 sporks, and 18 straws) by methanol extraction and non-targeted analysis using GC-Orbitrap HRMS. Subsequently, 14 high-risk substances were further screened and their migration in the samples was measured in three food simulants. Finally, based on the proposed safety limit assessment scheme for EU- authorized and unauthorized substances, the risk assessment of exposure to high-risk substances in disposable plastic tableware was performed for three age groups. The results showed that the dibutyl phthalate and bis(2-ethylhexyl) phthalate in some samples exceeded the safety limit value. Overall, the risk of bowls was lower than spock and straws, and the potential exposure risk for young children was higher than that of adults and older children.

Short- and medium-chain chlorinated paraffins in breast milk in Shanghai, China: Occurrence, characteristics, and risk assessment.

As novel contaminants, short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) have been of great concern in the past several years. Shanghai was one of the provinces with the largest chlorinated paraffins (CPs) emission in China; nevertheless, there is currently little information on the human exposure to SCCPs and MCCPs, particularly MCCPs. In this study, 25 breast milk samples were collected in Shanghai from 2016 to 2017. The concentrations of SCCPs and MCCPs were determined using two-dimensional gas chromatography coupled with orbitrap high-resolution mass spectrometry (GC × GC-orbitrap-HRMS) to investigate their characteristics and assess the associated health risks for breast-fed infants. Compared with the previous studies in other areas, the current study presented the higher CPs concentrations, with median concentrations of SCCPs and MCCPs up to 771 and 125 ng/g lipid weight (lw), respectively. The exposure profiles of the CPs were characterized by C10 and Cl6-7 as the predominant congeners of SCCPs, while C14 and Cl7-9 were identified as the dominant groups of MCCPs. CP-42 and CP-52 were identified as potential sources of CPs found in breast milk samples collected in Shanghai. The concentrations of MCCPs exhibited a positive correlation (p value < 0.05) with the dietary consumption of meat and poultry. No significant positive correlations were observed for SCCPs and MCCPs with polychlorinated dibenzodioxins/furans (PCDD/Fs) congeners. A preliminary exposure assessment showed that SCCPs in breast milk potentially posed high risks to the breast-fed infants in Shanghai.

Sensory-Guided Establishment of Sensory Lexicon and Investigation of Key Flavor Components for Goji Berry Pulp.

Many customers prefer goji berry pulp, well-known for its high nutritional content, over fresh goji berries. However, there is limited research on its sensory lexicon and distinctive flavor compounds. This study focused on developing a sensory lexicon for goji berry pulp and characterizing its aroma by sensory and instrumental analysis. Sensory characteristics of goji berry pulp were evaluated by our established lexicon. A total of 83 aromatic compounds in goji berry pulp were quantified using HS-SPME-GC-Orbitrap-MS. By employing OAV in combination, we identified 17 aroma-active compounds as the key ingredients in goji berry pulp. Then, we identified the potentially significant contributors to the aroma of goji berry pulp by combining principal component analysis and partial least squares regression (PLSR) models of aroma compounds and sensory attributes, which included 3-ethylphenol, methyl caprylate, 2-hydroxy-4-methyl ethyl valerate, benzeneacetic acid, ethyl ester, hexanal, (E,Z)-2,6-nonadienal, acetylpyrazine, butyric acid, 2-ethylhexanoic acid, 2-methyl-1-propanol, 1-pentanol, phenylethyl alcohol, and 2-nonanone. This study provides a theoretical basis for improving the quality control and processing technology of goji berry pulp.

Changes of the volatile compounds and odors in one-stage and three-stage infant formulas during their secondary shelf-life.

The odor of infant formula changes due to alterations in its volatile composition during the shelf life. However, there is currently a lack of research on whether the odor changes in infant formula during the secondary shelf life, which refers to the period of repeated opening and usage in daily life. This study used headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-electrostatic orbitrap high-resolution mass spectrometry (GC-Orbitrap-MS) to investigate the volatile composition changes in one-stage and three-stage infant formulas during different stages (0 day, 3 days, and 7 days during the secondary shelf-life, i.e. simulated daily use). A total of 32 volatiles were identified, including nine aldehydes, seven ketones, four alcohols, three furans, two sulfur compounds, two esters, and five terpenoids. Of these, 16 compounds changed significantly in one-stage samples and 23 compounds in three-stage samples within 7 days of the secondary shelf-life. Further the odor of the three-stage infant formula samples was found changed substantially after 3 days of simulated use by using the triangle test. This study highlighted the considerable alterations in volatile compound composition and sensory changes during the simulated daily use and provided valuable insights for consumers in selecting and using infant formula products, as well as a new perspective for enterprises to improve the sensory quality of their products.

Suspect and non-target screening of semi-volatile emerging contaminants in indoor dust from Danish kindergartens.

Indoor dust is a sink of hundreds of organic chemicals, and humans may potentially be exposed to these via indoor activities. This study investigated potentially harmful semi-volatile organic contaminants in indoor dust from Danish kindergartens using suspect and non-target screening on gas chromatography (GC)-Orbitrap, supported by target analyses using GC-low resolution mass spectrometry (LRMS). A suspect list of 41 chemicals with one or more toxicological endpoints, i.e. endocrine disruption, carcinogenicity, neurotoxicity and allergenicity, known or suspected to be present in indoor dust, was established including phthalate and non-phthalate plasticizers, flame retardants, bisphenols, biocides, UV filters and other plastic additives. Of these, 29 contaminants were detected in the indoor dust samples, also including several compounds that had been banned or restricted for years. In addition, 22 chemicals were tentatively identified via non-target screening. Several chemicals have not previously been detected in Danish indoor dust. Most of the detected chemicals are known to be potentially harmful for human health while hazard assessment of the remaining compounds indicated limited risks to human. However, children were not specifically considered in this hazard assessment.

Wide-Scope Multi-residue analysis of pesticides in beef by gas chromatography coupled with quadrupole Orbitrap mass spectrometry.

Increasing pesticide contamination in foods of animal origin has made the wide-scope multi-residue analysis of pesticides an international concern. By using 191 pesticides, this study investigates a sensitive and reliable method for multi-residue analysis of pesticides in beef to determine the extent of the application of this method. The QuEChERS method was employed to extract and purify the pesticides as C18 was utilized as the absorbents. Then, the purified pesticides were analysed using gas chromatography - quadrupole orbitrap mass spectrometry (GC-Q-Orbitrap-MS). The validation test results revealed that this method was satisfactorily sensitive since its screening detection limit (SDL) ranged from 0.2 to 100 µg∙kg-1. The recovery tests implemented at three spiking levels, namely 100, 200, and 500 µg∙kg-1, generated the results of 71.95 %-113.97 %, while the intra- and inter-day precisions were 0.27 %-17.94 %, indicating that this method had excellent accuracy and precision.

Investigation of aroma characteristics of seven Chinese commercial sunflower seed oils using a combination of descriptive Analysis, GC-quadrupole-MS, and GC-Orbitrap-MS.

The aroma characteristics of seven commercial Chinese sunflower seed oils were investigated in this study using descriptive analysis, headspace solid-phase microextraction coupled with GC-quadrupole-MS (LRMS, low-resolution mass spectrometry), and GC-Orbitrap-MS (HRMS, high-resolution mass spectrometry). GC-Orbitrap-MS quantified 96 compounds, including 18 alcohols, 12 esters, 7 ketones, 20 terpenoids, 11 pyrazines, 6 aldehydes, 6 furans, 6 benzene ring-containing compounds, 3 sulfides, 2 alkanes, and 5 nitrogen-containing compounds. Moreover, 22 compounds including 5 acids, 1 amide, and 16 aldehydes were quantified using GC-Quadrupole-MS. To our knowledge, 23 volatile compounds were reported for the first time in sunflower seed oil. All the seven samples were found to have a 'roasted sunflower seeds' note, 'sunflower seeds aroma' note and 'burnt aroma' note and only five of them had 'fried instant noodles' note, three had 'sweet' note and two had 'puffed food' note. Partial least squares regression was used to screen the candidate key volatiles that caused the aroma differences among these seven samples. It was observed that 'roasted sunflower seeds' note was positively correlated with 1-octen-3-ol, n-heptadehyde and dimethyl sulfone, whereas the 'fried instant noodles' and 'puffed food' demonstrated a positive correlation with pentanal, 3-methylbutanal, hexanal, (E)-2-hexenal and 2-pentylfuran. Our findings provide information to the producers and developers for quality control and improvement of sunflower seed oil.

An integrated untargeted metabolomic approach reveals the quality characteristics of black soybeans from different geographical origins in China.

Black soybeans are extensively planted and consumed in China due to their high nutritional value and numerous health benefits. However, very few is known about the characteristic metabolites of black soybeans from different geographical origins in China. In the present study, 31 black soybean samples were collected from 11 main producing provinces in China. A combined metabolomics approach using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and gas chromatography coupled to an Orbitrap mass analyzer (GC-orbitrap-MS) was performed for the first time to comprehensively investigate the metabolite variability among the black soybeans from different geographical origins. A total of 48 differential non-volatile metabolites and 14 differential volatile metabolites were identified based on orthogonal partial least squares discriminant analysis (OPLS-DA) coupled with analysis of variance (ANOVA). Higher procyanidin B1, procyanidin B2, epicatechin, malonylated isoflavones, and ß-pinene were observed in Gansu black soybeans. Guangxi black soybeans had higher amounts of linoleic acid and its oxidation products of hexanal and pentane. The black soybeans from Xinjiang and Yunnan were found to have higher delphinidin-derived anthocyanins, gamma-glutamyl peptides, and aromatic hydrocarbons. The characteristic metabolites of black soybeans from other geographical origins were also clarified. This study indicated that the integrated untargeted metabolomic approach can be a powerful tool to provide knowledge for developing specialty black soybeans.

[Screening of risky substances in sea cucumbers based on gas chromatography-orbitrap high-resolution mass spectrometry].

A new method for sample pretreatment using improved QuEChERs was established, and 289 organic pollutants with health risks could be identified and quantified through gas chromatography-orbitrap high-resolution mass spectrometry (GC-Orbitrap HRMS). A high-resolution database of 289 environmental pollutants belonging to ten categories, including organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), phthalates (PAEs), polychlorinated biphenyls (PCBs), and other agricultural chemicals (ACs), was established for the non-targeted screening and quantitative analysis. A simple method for biological sample preparation using improved QuEChERs was proposed by combining a conventional QuEChERs method and a column purification method. After purification using a Florisil column, the lipid content was reduced by 99.9%, which significantly reduced the interference of the matrix effect observed during the analysis. Furthermore, simultaneous high-accuracy qualitative screening and quantitative analysis of the target compounds were performed through high-resolution mass spectrometry (60000 resolution) conducted in the full scan mode. The limits of quantification were 0.56-57.8 pg/g, presenting a large linear range (~106), and the recovery range was 40%-120%. Due to the high-resolution and sensitivity of Q Exactive GC-Orbitrap HRMS, the limits of quantification of the target compounds were significantly lower than those achieved through methods based on conventional chromatography and mass spectrometry. Moreover, ultratrace organic contaminants that cannot be detected by conventional methods can be accurately quantified by the proposed method. Sea cucumber samples collected at the breeding site were analyzed using the proposed high-coverage multi-objective analytical method, and more than 100 types of organic pollutants were detected; the mean contents of PAHs, ACs, PAEs, and OCPs were 157.8, 153.2, 64.4, and 46.4 ng/g dw, respectively, which were higher than those of other pollutants. Some new contaminants, such as 9-chlorofluorene, 5-chloroacenaphthene, and 3-methylcholanthrene, were detected at very low contents for the first time in the sea cucumber samples. The proposed method is simple and efficient, allows the detection of pollutants at very low contents, and provides accurate and reliable results. Thus, this high-coverage multi-objective analytical method can be widely used for broad-spectrum screening and accurate quantification of contaminants in various aquatic products, providing technical support for food safety control.

Accurate Determination of 12 Lactones and 11 Volatile Phenols in Nongrape Wines through Headspace-Solid-Phase Microextraction (HS-SPME) Combined with High-Resolution Gas Chromatography-Orbitrap Mass Spectrometry (GC-Orbitrap-MS).

This paper clarifies the contribution of lactones and volatile phenols to the aroma of nongrape wine. A target method for the simultaneous determination of these two kinds of volatiles in nongrape wines was developed using headspace-solid-phase microextraction (HS-SPME) combined with high-resolution gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap-MS). A high-resolution mass spectrometry database including 12 lactones and 11 volatile phenols was established for qualitative accuracy. Different matrix-matched calibration standards should be prepared for specific samples due to the matrix effects. The method was successfully validated and applied in three nongrape wines. Hawthorn wine contained more lactones (δ/γ-hexalactone, δ/γ-nonalactone, δ/γ-decalactone, γ-undecalactone, δ/γ-dodecalactone, C10 massoia lactone, and whiskey lactone), while blueberry wine contained more volatile phenols (especially 4-vinylguaiacol and 4-ethylguiaiacol). Goji berry wines contained certain concentrations of δ-nonalactone, γ-nonalactone, δ-hexalactone, and 3-ethyl phenol. This study demonstrated that HS-SPME-GC-Orbitrap-MS can be applied for the accurate quantification of trace aroma compounds such as lactones and volatile phenols in fruit wines.

Non-targeted Gas Chromatography Orbitrap Mass Spectrometry qualitative and quantitative analysis of semi-volatile organic compounds in indoor dust using the Regions of Interest Multivariate Curve Resolution chemometrics procedure.

In this study, non-targeted gas chromatography-Orbitrap-mass spectrometry (GC-Orbitrap-MS) analysis of semi-volatile organic compounds (SVOCs) in indoor environmental dust samples is proposed. High-resolution mass spectrometry (HRMS) provides massive amounts of information-rich mass data which presents storage and processing challenges. Thus, a combination of the regions of interest (ROI) data filtering and mass compression method, together with the multivariate curve resolution-alternating least squares (MCR-ALS) data resolution method (which is called the ROIMCR procedure), is applied to solve huge data analysis challenges. The ROI method assures a significant reduction of the computer storage requirements of mass spectrometry data without any significant loss of spectral resolution nor of accuracy on m/z measures. On the other side, the MCR-ALS method allows the total resolution of the elution and spectral profiles of the different constituents present in the analyzed samples, not requiring their chromatographic peak alignment nor their chromatographic peak shape modelling using natural constraints like non-negativity. Since all the possible species are investigated by the ROIMCR method, it is a powerful tool for non-targeted analysis. In order to check that the sample constituents are correctly recovered and identified by the proposed ROIMCR procedure when is applied to non-targeted GC-Orbitrap-MS analysis, a set of lab-emulated dust samples at different concentration levels were qualitatively and quantitatively analyzed in detail. Then, to evaluate the performance of the proposed ROIMCR procedure, this method was applied to the same type of non-targeted GC-Orbitrap-MS analysis data of two real dust samples with unknown compositions. Many chemical compounds present in the lab-emulated dust samples were correctly identified and quantified in these dust samples. An additional number of extra chemical compounds were resolved in these real dust samples, whose identification as putative constituents of these samples is proposed. The ROIMCR procedure proposed in this work facilitates the simultaneous data processing of complex analytical samples and allows the detection and identification of possible extra sample constituents. As a final conclusion of this work, the combination of the GC-Orbitrap-MS and ROIMCR methods, is shown to be a reliable tool for the non-targeted qualitative and quantitative analysis of complex analytical and environmental samples.

Monitor process state of batch anaerobic digestion in reliance on volatile and semi-volatile metabolome.

It has been a challenge to recognize appropriate compounds as indicators for monitoring and early-warning of the anaerobic digestion process. A strategy was initiated to explore the evolution of the panorama profile of volatile and semi-volatile metabolites. Non-target analysis using high-resolution gas chromatography coupled with Orbitrap mass spectrometry was applied to construct a time-series molecular fingerprint of 218 metabolites classified in 14 categories. Alkanes accounted for the main part in early and late stages of methanization and aromatic compounds were the major in middle stage. Spearman correlation analysis and partial least squares analysis unwind that Trichococcus (1.49%-83.96%) was positively related to most of metabolites at early and middle stages, while Brevundimonas (0%-24.04%) was positively related to acylamide at late stage. This indicated that microbial volatile organic compounds were possible to serve as biochemical indicators for anaerobic digestion performance and to build nexus of "what" (metabolites), "who" (microorganism), and "how" (kinetics).

Non-targeted screening of chemicals migrating from paper-based food packaging by GC-Orbitrap mass spectrometry.

The aim of this study was to identify chemicals migrating from paper-based food packaging materials by GC-Orbitrap mass spectrometry (MS). Migration tests were conducted with samples of butcher paper, liquid egg containers, pizza boxes and pizza box liners. A new approach for an automated data processing of GC-Orbitrap EI data was developed and evaluated with Compound Discoverer™ software. A total of 35 migrated chemicals were putatively identified. They represented natural compounds, fatty acid ethyl esters, FDA substances added to food and Indirect Additives in Food Contact Substances, common phthalates, alkanes, siloxanes, ketones, and chemicals used as additives in packaging. Additionally, some unexpected compounds suspected to be degradation products of additives were identified. Levels of 23 identified chemicals significantly (p < 0.05) changed over the 10-day migration test. For two identified migrants, dibutyl phthalate and benzophenone, calculated specific migration limits (SMLs) were below the established regulatory levels. The information on the identity of chemicals migrating from food packaging materials is important to inform regulatory agencies and to develop risk management strategies.

Targeted and Nontargeted Detection and Characterization of Trace Organic Chemicals in Human Serum and Plasma Using QuEChERS Extraction.

Humans are exposed to a broad range of organic chemicals. Although targeted gas chromatography mass spectrometry techniques are used to quantify a limited number of persistent organic pollutants and trace organic contaminants in biological samples, nontargeted, high-resolution mass spectrometry (HRMS) methods assess the human exposome more extensively. We present a QuEChERS extraction for targeted and nontargeted analysis of trace organic contaminants using HRMS and compare this method to a traditional, cartridge-based solid-phase extraction (SPE). Following validation using reference and spiked serum samples, the method was applied to plasma samples (n = 75) from the Prospective investigation of Obesity, Energy, and Metabolism (POEM) study. We quantified 44 analytes using targeted analysis and 6247 peaks were detected using the nontargeted approach. Over 90% of targeted analytes were at least 90% recovered using the QuEChERS method in spiked serum samples. In nontargeted analysis, 84% of the peaks were above the method detection limit with area counts up to 3.0 × 105 times greater using the QuEChERS method. Of the targeted compounds, 88% were also identified in the nontargeted analysis. We categorized the 4212 chemicals assigned an identity in using EPA's CompTox Dashboard and 1076 chemicals were found in at least one list. The category with the highest number of chemicals was "androgen or estrogen receptor activity." The findings demonstrate that a QuEChERS technique is suitable for both targeted and nontargeted analysis of trace organic contaminants in biological samples.

Measurable Levels of Short-Chain Chlorinated Paraffins in Western Hudson Bay Fishes but Limited Biomagnification from Fish to Ringed Seals.

We investigated short-chain (C10-13 ) chlorinated paraffins (SCCP) in an Arctic marine food web. In zooplankton, fishes, and ringed seals from western Hudson Bay, Canada, SCCP concentrations ranged from 38.3 to 687 ng g-1 lipid weight. Monte Carlo-simulated trophic-adjusted biomagnification factors of individual SCCP congeners ranged from 0.07 to 0.55 for small pelagic fishes to seals. Despite relatively high concentrations in fishes, biomagnification of SCCPs within this food web appears limited. Environ Toxicol Chem 2021;40:2990-2999. © 2021 SETAC.

Rapid Screening of 350 Pesticide Residues in Vegetable and Fruit Juices by Multi-Plug Filtration Cleanup Method Combined with Gas Chromatography-Electrostatic Field Orbitrap High Resolution Mass Spectrometry.

A new method for screening pesticide residues in vegetable and fruit juices by the multi-plug filtration cleanup (m-PFC) method combined with gas chromatography-electrostatic field orbitrap high resolution mass spectrometry(GC-Orbitrap/MS) was developed. The samples were extracted with acetonitrile, purified with m-PFC and determined by GC-Orbitrap/MS. Qualitative analysis was confirmed by retention time, accurate molecular mass and quantitative analysis were performed with the matrix standard calibration. It could eliminate matrix interference effectively. Eight kinds of typical samples (orange juice, apple juice, grape juice, strawberry juice, celery juice, carrot juice, cucumber juice, tomato juice) were evaluated. The linear ranges of the 350 pesticides were from 5 to 500 µg/kg, with good correlation coefficients greater than 0.990. The limits of detection (LODs) were 0.3-3.0 µg/kg and the limits of quantification (LOQs) were 1.0-10.0 µg/kg. The average recoveries at three spiked levels of 10, 100, 200 µg/kg were in the range of 72.8-122.4%, with relative standard deviations (RSDs) of 2.0-10.8%. The method has effectively improved the determination efficiency of pesticide residue screening by high-resolution mass spectrometry in vegetable and fruit juices.

Exploration of environmental contaminants in honeybees using GC-TOF-MS and GC-Orbitrap-MS.

This study reports an analytical approach by gas chromatography and high-resolution mass spectrometry (HRMS) intended to be used for investigation of non-targeted environmental contaminants in honeybees. The approach involves a generic extraction and analysis with two GC-HRMS systems: time-of-flight and Orbitrap analyzers, GC-TOF-MS, and GC-Orbitrap-MS operated in electron-impact ionization (EI) mode. The workflow for screening of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, molecular formula of representative ions (molecular and fragment ions) was provided for those with an accurate mass scoring (error < 5 ppm). This methology was applied for screening environmental contaminants in 75 samples of adult honeybee. This approach has provided the tentative identification of environmental contaminants belonging to different chemical groups, among them, PAHs, phthalates and synthetic musks. Residues of veterinary treatments used in apiculture were also detected in the honeybee samples.

Non-targeted acquisition strategy for screening doping compounds based on GC-EI-hybrid quadrupole-Orbitrap mass spectrometry: A focus on exogenous anabolic steroids.

This is a first look at a non-targeted screening method based on Orbitrap gas chromatography-mass spectrometry (GC-MS) technology for a large number of banned compounds in sports found in urine, including exogenous anabolic steroids, ß-agonists, narcotics, stimulants, hormone modulators, and diuretics. A simple sample preparation was processed in four steps: an enzymatic hydrolysis, liquid-liquid extraction, evaporation, and trimethylsilylation. All compounds were able to meet the World Anti-Doping Agency's sensitivity criteria with mass accuracies less than 1 ppm and with sufficient points across the peak by running the Orbitrap GC-MS in full-scan mode. In addition, we discuss our initial findings of using a full-scan selected ion monitoring-tandem mass spectrometry (SIM-MS/MS) approach as a way to obtain lower detection limits and reach desirable selectivity for some exogenous anabolic steroids.