Atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry for simultaneous determination of fifteen organochlorine pesticides in soil and water

Determination of 3-nitropropionic acid in sugarcane using dispersive solid-phase extraction and gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry

A method for accurately determining 3-nitropropionic acid in sugarcane was established for the first time using gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (GC - APCI-MS/MS). Under acidic conditions, 3-nitropropionic acid is methylated to obtain methyl 3-nitropropionate. The derivative product was purified using dispersive solid-phase extraction (d-SPE) method and analyzed using GC - APCI-MS/MS. The recovery experiments were conducted at three concentrations: low, medium, and high. The recovery rates ranged from 75.1% to 90.2%, the relative standard deviations were <8.2%, and the limit of quantification was 2.0 μg/kg. The method offers the advantage of being accurate, sensitive, and specific, meeting the requirements of the determination of 3-nitropropionic acid in sugarcane.

Development and comprehensive SBSE-GC/Q-TOF-MS analysis optimization, comparison, and evaluation of different mulberry varieties volatile flavor

Optimization of seven parameters of stir bar sorptive extraction (SBSE) on mulberry volatile components for the first time. A total of 347 volatile components were identified and quantified in 14 mulberry varieties, predominantly encompassing esters, aldehydes, terpenoids, hydrocarbons, ketones, alcohols, heterocyclics, acids, and phenols. Hexanal and (E)-2-hexenal were the dominant volatiles. Furthermore, 79 volatile compounds characterized by odor activity values (OAVs) > 1 were identified, making a significant contribution to the distinctive mulberry flavor. "Green" notes were the most intense, followed by "fatty" and "fruity". Utilizing odor ring charts, the volatile flavor characteristics of the 14 mulberry varieties could be intuitively distinguished. This study not only established a viable methodology for differentiating mulberry varieties but also laid a theoretical foundation for the quality evaluation and variety breeding of mulberry flavor.

Benefits of Ion Mobility Separation in GC-APCI-HRMS Screening: From the Construction of a CCS Library to the Application to Real-World Samples

The performance of gas chromatography (GC) combined with the improved identification properties of ion mobility separation coupled to high-resolution mass spectrometry (IMS-HRMS) is presented as a promising approach for the monitoring of (semi)volatile compounds in complex matrices. The soft ionization promoted by an atmospheric pressure chemical ionization (APCI) source designed for GC preserves the molecular and/or quasi-molecular ion information enabling a rapid, sensitive, and efficient wide-scope screening. Additionally, ion mobility separation (IMS) separates species of interest from coeluting matrix interferences and/or resolves isomers based on their charge, shape, and size, making IMS-derived collision cross section (CCS) a robust and matrix-independent parameter comparable between instruments. In this way, GC-APCI-IMS-HRMS becomes a powerful approach for both target and suspect screening due to the improvements in (tentative) identifications. In this work, mobility data for 264 relevant multiclass organic pollutants in environmental and food-safety fields were collected by coupling GC-APCI with IMS-HRMS, generating CCS information for molecular ion and/or protonated molecules and some in-source fragments. The identification power of GC-APCI-IMS-HRMS for the studied compounds was assessed in complex-matrix samples, including fish feed extracts, surface waters, and different fruit and vegetable samples.

Current Role of Mass Spectrometry in the Determination of Pesticide Residues in Food

The extensive use of pesticides represents a risk to human health. Consequently, legal frameworks have been established to ensure food safety, including control programs for pesticide residues. In this context, the performance of analytical methods acquires special relevance. Such methods are expected to be able to determine the largest number of compounds at trace concentration levels in complex food matrices, which represents a great analytical challenge. Technical advances in mass spectrometry (MS) have led to the development of more efficient analytical methods for the determination of pesticides. This review provides an overview of current analytical strategies applied in pesticide analysis, with a special focus on MS methods. Current targeted MS methods allow the simultaneous determination of hundreds of pesticides, whereas non-targeted MS methods are now applicable to the identification of pesticide metabolites and transformation products. New trends in pesticide analysis are also presented, including approaches for the simultaneous determination of pesticide residues and other food contaminants (i.e., mega-methods), or the recent application of techniques such as ion mobility–mass spectrometry (IM–MS) for this purpose.

Distribution and Estrogenic Risk of Alkylphenolic Compounds, Hormones and Drugs Contained in Water and Natural Surface Sediments, Morelos, Mexico

This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol A (BPA), 4-nonylphenol (4NP), naproxen (NPX), ibuprofen (IBU), 17-β-estradiol (E2) and 17-α-ethinylestradiol (EE2) in water and sediments of the Apatlaco river micro-basin (Morelos, Mexico). The concentration of the determined compounds ranged between <LOD to 86.40 ng·L−1 and <LOD to 3.97 ng g−1 in water and sediments, respectively. The Log Kd distribution obtained (from 1.05 to 1.91 L Kg−1) indicates that the compounds tend to be adsorbed in sediments, which is probably due to the hydrophobic interactions confirmed by the significant correlations determined mainly between the concentrations and parameters of total organic carbon (TOC), total suspended solids (TSS), biological oxygen demand (BOD5) and chemical oxygen demand (COD). Of five sites analyzed, four presented estrogenic risk due to the analyzed endocrine-disrupting compounds (EEQE2 > 1 ng·L−1).

Mesoporous silica sorbent with gold nanoparticles for solid-phase extraction of organochlorine pesticides in water samples

In this work, a novel sorbent, based on UVM-7 mesoporous silica doped with Au, has been proposed for organochlorine pesticides extraction. Cartridges containing this material have been applied to the preconcentration of 20 pesticides from water samples, through a solid-phase extraction (SPE) protocol, with their later determination by gas chromatography with an electron capture detector. First, UVM-7 materials were properly characterized by X-ray diffraction, N₂ adsorption-desorption, electron microscopy techniques, and UV-Vis spectroscopy, thus confirming their structure and Au incorporation. After optimization of main extraction parameters, recoveries in the range of 80-110% were obtained for most of the analytes, with enrichment factors comprised between 275 and 430. The obtained sensitivity was comparable with other reported methods, with limits of quantification in the range of 0.3-20 ng L^-1, thus allowing the determination of these compounds according to European legislation. The developed method has been successfully applied to the analysis of real spiked samples in comparison with a reference method, thus being this sorbent an alternative for organochlorine pesticide enrichment, through a simple, reusable, cheap, and environmentally friendly SPE procedure.

Gas Chromatography Coupled to Atmospheric Pressure Chemical Ionization High-Resolution Mass Spectrometry for Metabolite Fingerprinting of Grape (Vitis vinifera L) Berry

This chapter describes the application of atmospheric pressure chemical ionization in conjunction with gas chromatography (APGC) coupled to high-resolution mass spectrometry for profiling metabolites in plant and fruit extracts. The APGC technique yields molecular ions and limited fragmentation of volatile or derivatized compounds. The data-independent acquisition mode, MS^E, was used for measuring precursor and fragment ions with high resolution using a quadrupole ion mobility time-of-flight mass spectrometry system. We demonstrate the importance of acquiring accurate mass information in conjunction with accurate mass fragment ions for efficient database searching and compound assignments with high confidence. We demonstrate the application of APGC-MS^E for obtaining metabolite data for grape berry extracts after derivatization.

Development of a quantitative screening method for pesticide multiresidues in orange, chili pepper, and brown rice using gas chromatography-quadrupole time of flight mass spectrometry with dopant-assisted atmospheric pressure chemical ionization

A rapid screening method for the quantitative analysis of pesticide multiresidues using a high-resolution accurate mass (HRAM) quadrupole time-of-flight (Q-TOF) with a dopant-assisted gas chromatography-atmospheric pressure chemical ionization (GC-APCI) technique were developed. For convenient and constant supply of APCI dopant, a large-volume dopant bottle with a bypass valve was newly designed, and the developed method was tested with 415 pesticide mixtures for representative produce (orange, chili pepper, and brown rice). Methanol-enriched nitrogen gas was used to produce protonated molecular [M + H]⁺ ions, and fragment ions were produced by broad-band collision-induced dissociation mode. Twenty representative pesticides were selected and validated for analytical performance. The methanol dopant-assisted GC-APCI-Q-TOF technique is very promising for target and non-target screening and sensitive quantification for hundreds of pesticides in a single run.

Characterization of raw and ozonated oil sands process water utilizing atmospheric pressure gas chromatography time-of-flight mass spectrometry combined with solid phase microextractionun

This work describes a novel application of atmospheric pressure gas chromatography time-of-flight mass spectrometry (APGC-TOF-MS) combined with solid-phase microextraction (SPME) for the simultaneous analysis of hydrocarbons and naphthenic acids (NAs) species in raw and ozone-treated oil sands process water (OSPW). SPME method using polydimethylsiloxane (PDMS)-coated fibers was validated using gas chromatography with flame ionization detector (GC-FID) to ensure the SPME extractions were operated appropriately. The ionization pathways of the hydrocarbon species in OSPW in the APGC source were verified by analyzing a mixture of eight polyaromatic hydrocarbons which were ionized primarily via charge transfer to produce [M⁺] while NAs in OSPW were found to be ionized through protonation to generate [MH⁺] in the wet APGC source. SPME/APGC-TOF-MS analysis demonstrated a different composition profile in OSPW #1, with 74.5% of hydrocarbon species, 23.4% of O₂-NAs, and 2.1% of the oxidized NA species at extraction pH 2.0 compared with that obtained by UPLC-TOF-MS analysis (36.9% of O₂-NAs, 26.8% of O₃-NAs, 24.9% of O₄-NAs, 9.1% of O₅-NAs, 2.3% of O₆-NAs). Moreover, the peak areas of the total NAs and the total peak areas of NAs + hydrocarbons measured by SPME/APGC-TOF-MS correlated excellently with the total NA concentration determined by UPLC-TOF-MS (R² = 0.90) and the concentrations of the total acid-extractable organics determined by SPME/GC-FID (R² = 0.98), respectively. APGC-TOF-MS integrated with the SPME techniques could extend the range of target compounds and be a promising alternative to evaluate and characterize NAs and hydrocarbon in different water types.

Multi-residue determination of pesticides in green tea by gas chromatography-tandem mass spectrometry with atmospheric pressure chemical ionisation using nitrogen as the carrier gas

Helium is commonly used as a carrier gas in gas chromatography-tandem mass spectrometry (GC-MS/MS); however, there are growing concerns regarding its global shortage and the resulting limited supply and high cost. Using nitrogen as an alternative carrier gas in GC-MS/MS with the widely used electron ionisation (EI) technique leads to a significantly lower sensitivity; thus, in this study, we explored the use of atmospheric-pressure chemical ionisation (APCI) as the ionisation method and examined the applicability of GC-(APCI)MS/MS with nitrogen gas for the determination of pesticide residues. GC-(APCI)MS/MS using nitrogen provided slightly wider peaks, and poorer isomeric separation compared to those using helium under identical conditions; however, the peak intensities were comparable. GC-(APCI)MS/MS using nitrogen was validated for 166 pesticides in green tea at a spiking level of 0.01 mg/kg and was compared with the conventional GC-(EI)MS/MS using helium gas. Except dimethomorph and resmethrin, GC-(APCI)MS/MS showed satisfactory results that were comparable to those of GC-(EI)MS/MS for most compounds, with trueness in the range of 73%-95% and relative standard deviations of <11%. The sensitivity and selectivity of GC-(APCI)MS/MS with nitrogen were superior to those of GC-(EI)MS/MS with helium. Therefore, GC-(APCI)MS/MS using nitrogen as the carrier gas, which has minimal concerns related to availability, could be a promising alternative to the conventional GC-(EI)MS/MS technique that employs helium.

Determination of Organochlorines in Soil of a Suburban Area of São Paulo Brazil

Technological advances have promoted improvements in several science fields, especially related to environmental and analytical areas with the improvement of detection and development of environmentally friendly extraction techniques. This study applied Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) for soil extraction and assessed its performance through a validation study using samples from the soil of a contaminated area in Caieiras, SP, Brazil. Nine organochlorine pesticides, including the isomers alpha, beta, gamma and delta- hexachlorocyclohexane; cis- and trans-heptachlor epoxide; cis- and trans-chlordane and heptachlor were analyzed by gas chromatography coupled to electron capture detector. The method was validated according to ISO 5725-4 (2020), EURACHEM (2014) and DOQ-CGCRE-008 (2016). The limits of detection and quantification of the method for the nine organochlorines were α-HCH (1.2 and 12.6 µg kg^-1), β-HCH (1.7 and 12.0 µg kg^-1), γ-HCH (1.5 and 11.6 µg kg^-1), δ-HCH (0.8 and 11.6 µg kg^-1), heptachlor (1.0 and 10.8 µg kg^-1), cis-heptachlor epoxide (0.9 and 11.5 µg kg^-1), trans-heptachlor epoxide (0.9 and 11.5 µg kg^-1), cis-chlordane (0.4 and 7.9 µg kg^-1) and trans-chlordane (0.5 and 10.9 µg kg^-1), respectively, and all of them were within the maximum limits recommended by the EPA for the compounds α-HCH (86.0 and 360.0 µg kg^-1), β-HCH (300.0 and 1.3 × 10³ µg kg^-1), γ-HCH (570.0 and 2.5 × 10³ µg kg^-1), δ-HCH (not defined), heptachlor (130.0 and 630.0 µg kg^-1), cis-/trans-heptachlor epoxide (7.0 and 330.0 µg kg^-1), cis-/trans-chlordane (1.77 × 10³ and 7.7 × 10³ µg kg^-1) in residential and industrial soil, respectively. Recovery results were between 65% and 105% for almost all compounds, which is an optimum result for multi-residue analytical methods, considering the complexity of the matrix used in the study. Caieiras presented contamination levels of α-HCH in the range of 2.0 to 66.0 µg g^-1, which was higher than the limits established by EPA, corresponding to 0.077 µg g^-1 for residential soil and 0.27 µg g^-1 for industrial soil. According to the validation study, the analytical method proposed was reliable for organochlorine quantification, and the QuEChERS was considered efficient for organochlorine extraction from soil.

Magnetic solid phase extraction using Fe3O4@β-cyclodextrin–lipid bilayers as adsorbents followed by GC-QTOF-MS for the analysis of nine pesticides

A rapid method for the analysis of trace organochlorine pesticides in a complex matrix.

Determination of volatile non intentionally added substances coming from a starch-based biopolymer intended for food contact by different gas chromatography-mass spectrometry approaches

The rapid growth of polymer technology in the field of food contact materials (FCMs) needs to be supported by continuous improvement in material testing, in order to ensure the safety of foodstuff. In this work, a range of different starch-based biopolymer samples, in the shape of pellets and retail samples (cups and dishes) were studied. The optimized extraction process was performed on three different pellet shapes: pellets with no modification (spherical), pellets shattered under high pressure (lentils), and pellets cryogenically ground (powder). The analysis of unknown volatile and semi-volatile compounds was carried out by gas chromatography-mass spectrometry, using both electron ionization with a single quadrupole mass analyzer (GC-EI-MS), and atmospheric pressure gas chromatography with a quadrupole/time of flight mass analyzer (APGC-Q/ToF). The identification process was implemented using the latest advances in the understanding of APGC ionization pathways. Chemical migration was also assessed on prototype samples using the food simulants: ethanol 10% v/v, acetic acid 3% w/V, ethanol 95% v/v, isooctane, and vegetable oil. Each migration test was performed three consecutive times, as recommended for materials intended for repeated use.

QuEChERS - Fundamentals, relevant improvements, applications and future trends

The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method is a simple and straightforward extraction technique involving an initial partitioning followed by an extract clean-up using dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS approach was developed for recovering pesticide residues from fruits and vegetables, but rapidly gained popularity in the comprehensive isolation of analytes from different matrices. According to PubMed, since its development in 2003 up to November 2018, about 1360 papers have been published reporting QuEChERS as extraction method. Several papers have reported different improvements and modifications to the original QuEChERS protocol to ensure more efficient extractions of pH-dependent analytes and to minimize the degradation of labile analytes. This analytical approach shows several advantages over traditional extraction techniques, requiring low sample and solvent volumes, as well as less time for sample preparation. Furthermore, most of the published studies show that the QuEChERS protocol provides higher recovery rate and a better analytical performance than conventional extraction procedures. This review proposes an updated overview of the most recent developments and applications of QuEChERS beyond its original application to pesticides, mycotoxins, veterinary drugs and pharmaceuticals, forensic analysis, drugs of abuse and environmental contaminants. Their pros and cons will be discussed, considering the factors influencing the extraction efficiency. Whenever possible, the performance of the QuEChERS is compared to other extraction approaches. In addition to the evolution of this technique, changes and improvements to the original method are discussed.

First application of atmospheric-pressure chemical ionization gas chromatography tandem mass spectrometry to the determination of cannabinoids in serum

The analysis of cannabinoids in blood samples is still a challenging issue for forensic laboratories, because of the low concentrations to be determined to prove that a person acted under CannabisTherefore, sensitive analytical techniques are required. This study presents the development and validation of a novel APGC-MS/MS method for the simultaneous determination of Δ9-tetrahydrocannabinol (THC), 11-hydroxy- Δ9-THC (THC-OH), 11-nor-9-carboxy- Δ9-THC (THCA), cannabidiol (CBD), cannabidiol acid (CBDA) and cannabigerol (CBG) in human serum. The developed method was fully validated according to international guidelines, with evaluation of selectivity, precision, accuracy, linearity, LODs and LOQs, extraction recovery and matrix effect. The method was linear in the range 0.2-25 ng/mL for THC, THC-OH, CBD and CBG, while for THCA and CBDA linearity was assessed in the range of 0.8-100 ng/mL and 3-100 ng/mL, respectively. The LOQs were determined in 0.2 ng/mL for THC, 0.4 ng/mL for THC-OH, 0.8 ng/mL for CBD and CBG, 1.6 ng/mL for THCA and 3 ng/mL for CBDA. The method was applied to the analysis of 15 serum samples from DUID cases. To the best of our knowledge, the present work is the first one describing an application of APGC source in the field of forensic toxicology.

Affinity Sensing Strategies for the Detection of Pesticides in Food

This is a review of recent affinity-based approaches that detect pesticides in food. The importance of the quantification and monitoring of pesticides is firstly discussed, followed by a description of the different approaches reported in the literature. The different sensing approaches are reported according to the different recognition element used: antibodies, aptamers, or molecularly imprinted polymers. Schemes of detection and the main features of the assays are reported and commented upon. The large number of affinity sensors recently developed and tested on real samples demonstrate that this approach is ready to be validated to monitor the amount of pesticides used in food commodities.