Rapid screening and quantification of residual pesticides and illegal adulterants in red wine by direct analysis in real time mass spectrometry

Recent advances in the application of direct analysis in real time-mass spectrometry (DART-MS) in food analysis

Direct analysis in real time-mass spectrometry (DART-MS) has evolved as an effective analytical technique for the rapid and accurate analysis of food samples. The current advancements of DART-MS in food analysis are described in this paper. We discussed the DART principles, which include devices, ionization mechanisms, and parameter settings. Numerous applications of DART-MS in the fields of food and food products analysis published during 2018-2023 were reviewed, including contamination detection, food authentication and traceability, and specific analyte analysis in the food matrix. Furthermore, the challenges and limitations of DART-MS, such as matrix effect, isobaric component analysis, cost considerations and accessibility, and compound selectivity and identification, were discussed as well.

Rapid authentication of red wine by MALDI-MS combined with DART-MS

A simple, rapid and high-throughput approach was developed for authentication of red wine for the first time, by combining spectral results from matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and direct analysis in real time mass spectrometry (DART-MS). By coupling with orthogonal partial least squares discrimination analysis (OPLS-DA), this approach enabled successful classification of 535 wines from 8 countries, with the correct classification rates of 100% on the calibration set and over 90% on the validation set for almost all countries, and 26 potential characteristic markers selected. Compared to one single technique, this approach allowed detection of more compound ions, and with better fitting and predictive performances. The satisfactory differentiation results of vintages and grape varieties further verified the robustness of the approach. This study demonstrated the feasibility of combining multiple mass spectrometric techniques for wine analysis, which can be extended to other fields or to combinations of other analytical techniques.

Sweeteners in food samples: An update on pretreatment and analysis techniques since 2015

Sweeteners play an irreplaceable role in daily life and have been found in multitudinous food products. However, excessive or unreasonable intake of sweeteners as food additives brings about untoward problems due to the accumulation in the human body. Therefore, a comprehensive review of different sweeteners' pretreatment and determination methods is urgently needed. In this review, we comprehensively reviewed the progress of different pretreatment and detection methods for sweeteners in various food, focusing on the latest development since 2015. Current state-of-the-art technologies, such as headspace single-drop microextraction, ultrasound-assisted emulsification microextraction, solid-phase microextraction, two-dimensional liquid chromatography, and high-resolution mass spectrometry, are thoroughly discussed. The advantages, disadvantages, critical comments, and future perspectives are also proposed. This review is expected to provide rewarding insights into the future development and broad application of pretreatment and detection methods for sweeteners in different food samples.

Routine analysis of pesticides in foodstuffs: Emerging ambient ionization mass spectrometry as an alternative strategy to be on your radar

Pesticides residues in foodstuffs are longstanding of great concern to consumers and governments, thus reliable evaluation techniques for these residues are necessary to ensure food safety. Emerging ambient ionization mass spectrometry (AIMS), a transformative technology in the field of analytical chemistry, is becoming a promising and solid evaluation technology due to its advantages of direct, real-time and in-situ ionization on samples without complex pretreatments. To provide useful guidance on the evaluation techniques in the field of food safety, we offered a comprehensive review on the AIMS technology and introduced their novel applications for the analysis of residual pesticides in foodstuffs under different testing scenarios (i.e., quantitative, screening, imaging, high-throughput detection and rapid on-site analysis). Meanwhile, the creative combination of AIMS with high-resolution mass analyzer (e.g., orbitrap and time-of-flight) was fundamentally mentioned based on recent studies about the detection and evaluation of multi-residual pesticides between 2015 and 2021. Finally, the technical challenges and prospects associated with AIMS operation in food industry were discussed.

A Novel Integrated APCI and MPT Ionization Technique as Online Sensor for Trace Pesticides Detection

The misuse of pesticides poses a tremendous threat to human health. Excessive pesticide residues have been shown to cause many diseases. Many sensor detection methods have been developed, but most of them suffer from problems such as slow detection speed or narrow detection range. So, the development of rapid, direct and sensitive means of detecting trace amounts of pesticide residues is always necessary. A novel online sensor technique was developed for direct analysis of pesticides in complex matrices with no sample pretreatment. The portable sensor ion source consists of an MPT (microwave plasma torch) with desolventizing capability and an APCI (atmosphere pressure chemical ionization), which provides abundant precursor ions and a strong electric field. The performance which improves the ionization efficiency and suppresses the background signal was verified by using pesticide standard solution and pesticide pear juice solution measurements with an Orbitrap mass spectrometer. The limit of detection (LOD) and the limit of quantization (LOQ) of the method were measured by pear juice solutions that were obtained in the ranges of 0.034-0.79 μg/L and 0.14-1 μg/L. Quantitative curves were obtained ranging from 0.5 to 100 μg/L that showed excellent semi-quantitative ability with correlation coefficients of 0.985-0.997. The recoveries (%) of atrazine, imidacloprid, dimethoate, profenofos, chlorpyrifos, and dichlorvos were 96.6%, 112.7%, 88.1%, 85.5%, 89.2%, and 101.9% with the RSDs ranging from 5.89-14.87%, respectively. The results show that the method has excellent sensitivity and quantification capability for rapid and direct detection of trace pesticide.

Origin, Succession, and Control of Biotoxin in Wine

Wine is a worldwide alcoholic beverage with antioxidant active substances and complex flavors. Moderate drinking of wine has been proven to be beneficial to health. However, wine has some negative components, such as residual pesticides, heavy metals, and biotoxins. Of these, biotoxins from microorganisms were characterized as the most important toxins in wine. Wine fermentation mainly involves alcoholic fermentation, malolactic fermentation, and aging, which endue wine with complex flavors and even produce some undesirable metabolites. These metabolites cause potential safety risks that are not thoroughly understood. This review aimed to investigate the origin, evolution, and control technology of undesirable metabolites (e.g., ochratoxin A, ethyl carbamate, and biogenic amines) in wine. It also highlighted current wine industry practices of minimizing the number of biotoxins in wine.

Accurate mass screening of pesticide residues in wine by modified QuEChERS and LC-hybrid LTQ/Orbitrap-MS

In this research, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure and Ultra-High Performance Liquid Chromatography-Orbitrap-Mass Spectrometry (UHPLC-Orbitrap-MS), were combined to obtain a sensitive and rapid method for the determination of multiclass pesticides in white and red wines. The optimization strategy involved the selection of buffering conditions, by applying different QuEChERS procedures and sorbents for the cleanup step in order to achieve acceptably high recoveries and low co-extractives in the final extracts. Identification was based on both accurate mass and retention time, while further confirmation was achieved by MS fragmentation. The method was evaluated in terms of linearity, recovery, precision, limit of detection (LOD) and quantification (LOQ), matrix effects (ME) and expanded uncertainty. The validated method was successfully applied to real samples (home-made and commercial) revealing the presence of two selected fungicides, in relatively low levels compared to the MRLs defined by the EU for vinification grapes.

Applications of direct analysis in real time mass spectrometry in food analysis: A review

RATIONALE

Direct analysis in real time (DART) combined with mass spectrometry (MS) detection has become one of the most broadly used analytical approaches for the direct molecular characterization of food samples with regard to their chemical quality, safety, origin, and authentication. The major advantages of DART-MS for food analysis include high chemical sensitivity and specificity, high speed and throughput of analysis, simplicity, and the obviation of tedious sample preparation and solvents.

METHODS

The recent applications of DART coupled with different mass analyzers, including quadrupole, ion trap, Orbitrap, and time of flight, are discussed. In addition, sample pretreatment methods that have been coupled with DART-MS are discussed.

RESULTS

We summarize the applications of DART-MS in food science and industry published in the period from 2005 to this date. The applications and analytical characteristics are systematically categorized across the three major types of foods: solid foods, liquid foods, and viscous foods.

CONCLUSIONS

DART-MS has proved its high suitability for the direct, rapid, and high-throughput molecular analysis of very different food samples with minimal or no sample preparation, thus offering a high-speed alternative to liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS) approaches that are traditionally employed in food analysis.

Structural identification of sour compounds in wine and tea by ambient ionization mass spectrometry according to characteristic product ion and neutral loss

Sourness is an important food taste for human. A rapid, accurate method was used to generalize the structure similarity and diversity of sour compounds. Based on the product ion and neutral loss of sour compounds, ambient ionization techniques combined with quadrupole-Orbitrap mass spectrometry (AI-Q-Orbitrap) was employed. According to the behavior of sour compounds in the process of high collision dissociation (HCD) of MS/MS, three fragmentation pathway schemes were proposed: (1) charge-driven fragmentation and CO₂ loss, (2) six-membered ring rearrangement and C_α-C_β cleavage, and (3) elimination rearrangement and H₂O, CO₂ and CO loss in succession. Besides, structure information about characteristic product ions and characteristic neutral losses was summarized. Finally, multi-class sour compounds including monoacids, diacids, polyacids and phenolic acids in wine and tea were identified and compared. Therefore, sour compounds and their structure information can be determined by AI-MS based on characteristic product ion and neutral loss.

Analytical Strategies for Fingerprinting of Antioxidants, Nutritional Substances, and Bioactive Compounds in Foodstuffs Based on High Performance Liquid Chromatography-Mass Spectrometry: An Overview

New technology development and globalisation have led to extreme changes in the agri-food sector in recent years that need an important food supply chain characterisation from plant materials to commercial productions. Many analytical strategies are commonly utilised in the agri-food industry, often using complementary technologies with different purposes. Chromatography on-line coupled to mass spectrometry (MS) is one of the most selective and sensitive analytical methodologies. The purpose of this overview is to present the most recent MS-based techniques applied to food analysis. An entire section is dedicated to the recent applications of high-resolution MS. Covered topics include liquid (LC)– and gas chromatography (GC)–MS analysis of natural bioactive substances, including carbohydrates, flavonoids and related compounds, lipids, phenolic compounds, vitamins, and other different molecules in foodstuffs from the perspectives of food composition, food authenticity and food adulteration. The results represent an important contribution to the utilisation of GC–MS and LC–MS in the field of natural bioactive compound identification and quantification.

Ambient (desorption/ionization) mass spectrometry methods for pesticide testing in food: a review

Ambient mass spectrometry refers to the family of techniques that allows ions to be generated from condensed phase samples under ambient conditions and then, collected and analysed by mass spectrometry. One of their key advantages relies on their ability to allow the analysis of samples with minimal to no sample workup. This feature maps well to the requirements of food safety testing, in particular, those related to the fast determination of pesticide residues in foods. This review discusses the application of different ambient ionization methods for the qualitative and (semi)quantitative determination of pesticides in foods, with the focus on different specific methods used and their ionization mechanisms. More popular techniques used are those commercially available including desorption electrospray ionization (DESI-MS), direct analysis on real time (DART-MS), paper spray (PS-MS) and low-temperature plasma (LTP-MS). Several applications described with ambient MS have reported limits of quantitation approaching those of reference methods, typically based on LC-MS and generic sample extraction procedures. Some of them have been combined with portable mass spectrometers thus allowing "in situ" analysis. In addition, these techniques have the ability to map surfaces (ambient MS imaging) to unravel the distribution of agrochemicals on crops.

Quantification of artificial sweeteners in alcoholic drinks using direct analysis in real-time QTRAP mass spectrometry

Artificial sweeteners have been widely used as replacements for sugars in foods. Rapid determination of artificial sweeteners contained in various foods are highly desirable for the routine analysis. Here, we report a robust approach based on direct analysis in real time coupled with QTRAP mass spectrometry to screen and quantitate simultaneously seven artificial sweeteners, including aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate and alitame in alcoholic drinks. The detection method merely involved a simple sample pretreatment process, with a good linearity, low limit of quantification, satisfied recovery and relative standard deviation for each target compound. More importantly, the approach is highly sensitive and accurate in monitoring the seven artificial sweeteners in whisky, Chinese liquors, beer and wines obtained from the supermarket. The results demonstrated that the approach described here could be suitable for large-scale application in routine quality control analysis of artificial sweeteners.

Rapid characterization of Schisandra species by using direct analysis in real time mass spectrometry

Direct analysis in real time ionization source coupled with quadrupole orbitrap mass spectrometry (DART-Q-Orbitrap MS) was applied to analyze the Schisandra chinensis (S. chinensis) and Schisandra sphenanthera (S. sphenanthera) samples. The experimental condition including the ionization gas and gas temperature were optimized to obtain the best performance. The DART-MS analysis was operated using helium at 250 °C. The partial least squares discriminant analysis (PLS-DA) was conducted based on the DART-MS data to explore the differences between S. chinensis and S. sphenanthera samples. The clear separation between groups was observed in the PLS-DA score plot, indicating the chemome diversity of these two samples. Then 8 compounds that contribute most to the sample classification were selected and annotated, and the intensity change tendency of these compounds was similar to that obtained by the high-performance liquid chromatography (HPLC) method. Besides, these two species can also be discriminated by examining the existence of the compound anwulignan at m/z 328.1656 in this study. Our results show that DART-MS is a powerful analytical tool with the merit of rapid analysis speed, easy to handle, low consumption of organic solvent, and has the great potential for rapid detection and discrimination of S. chinensis and S. sphenanthera. It is expected that the established method could provide a rapid, reliable method for the quality assessment of Schisandra species, and expand this method to the analysis of other herbal medicines.

Miniaturized QuEChERS method for determination of 97 pesticide residues in wine by ultra-high performance liquid chromatography coupled with tandem mass spectrometry

A miniaturized sample preparation method was developed and validated for the multiresidue determination of 97 pesticides in wine samples. The proposed extraction procedure is based on the QuEChERS acetate method with dispersive solid phase extraction (d-SPE) for the clean-up step. Ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was used for determination. The extraction and clean-up steps were evaluated to obtain the best conditions for the selected pesticides. Miniaturization of the sample preparation step provided a reduction in the consumption of samples and chemicals. The method limit of quantification was between 10 and 20 μg L-1. Trueness results, obtained by recovery assays at the spike levels 10, 20, 50 and 100 μg L-1, ranged from 70 to 120% with precision in terms of relative standard deviations (RSD) ≤ 20%. The method was successfully applied for the analysis of wine samples and different pesticides were found at concentrations from 14 to 55 μg L-1.

Detection of pesticide residues on intact tomatoes by carbon fiber ionization mass spectrometry

Trace and toxic pesticide residues may still remain on crops after harvest. Thus, maximum residual levels (MRLs) of pesticides on crops have been regulated. To determine whether the remaining pesticide residue level is below MRL, time-consuming sample pretreatment is needed prior to analysis of crop samples by suitable analytical tools. By elimination of sample pretreatment steps, a high-throughput method can be developed to determine the presence of pesticide residues directly on intact crops. Carbon fiber ionization mass spectrometry (CFI-MS) is effective in determining analytes with different polarities in solid, liquid, and vapor phases in open air. Moreover, the vapor derived from solid or liquid samples possessing high vapor pressure can be readily detected by CFI-MS. The setup of CFI-MS is straightforward. A carbon fiber (diameter of ~ 10 μm and length of ~ 1 cm) is placed close (~ 1 mm) to the inlet of the mass spectrometer applied with a high voltage (- 4.5 kV). No direct electrical contact applied on the carbon fiber is required. When placing the sample with certain vapor pressure underneath the carbon fiber, analyte ions derived from the sample can be readily detected by the mass spectrometer. Given that most pesticides possess a certain vapor pressure (~ 1.33 × 10^-5-~ 1.33 × 10^-4 Pa), we herein develop a qualitative and quantitative analysis method to determine pesticide residues on intact fruits such as tomato based on CFI-MS without requiring any sample pretreatment. Atrazine, ametryn, carbofuran, chlorpyrifos, isoprocarb, and methomyl were selected as model samples. Low limits of detection (at nM range) were achieved for the model pesticides using the current approach. Moreover, we demonstrated that the precision and accuracy of quantitative analysis of ~ 5% and ~ 2%, respectively, could be achieved using this approach. Graphical Abstract ᅟ.

Rapid Analysis of Ingredients in Cream Using Ultrasonic Mist-Direct Analysis in Real-Time Time-of-Flight Mass Spectrometry

A novel method for the simultaneous detection of ingredients in pharmaceutical applications such as creams and lotions was developed. An ultrasonic atomizer has been used to produce a mist containing ingredients. The analyte molecules in the mist can be ionized by using direct analysis in real time (DART) at lower temperature than traditionally used, and we thus solved the problem of normal DART-MS measurement using a high-temperature gas. Thereby, molecular-related ions of heat-unstable components and nonvolatile components became detectable. The deprotonated molecular ion of glycyrrhizic acid (m/z 821), which is unstable at high temperatures, was detected without pyrolysis by ultrasonic mist-DART-MS using unheated helium gas, although it was not detected by normal DART-MS using heated helium gas. The cationized molecular ions of derivatives of polyethylene glycol fatty acid monoesters, which are nonvolatile compounds, were also detected as m/z peaks observed from 800 to 2300. Although the protonated molecular ion of tocopherol acetate was not detected in ionization by ultrasonic mist, it was detected by ultrasonic mist-DART-MS even in the emulsion. It was not necessary to dissolve a sample completely to detect its ions. This method enabled us to obtain the composition of pharmaceutical applications simply and rapidly. Graphical Abstract ᅟ.

Highly efficient degradation of thidiazuron with Ag/AgCl- activated carbon composites under LED light irradiation

Thidiazuron (TDZ; 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea) is one of the most widely used defoliant and easy to dissolve in surface water. Risk associated with the pesticide is not clearly defined, so it is important to remove/degrade TDZ with an efficient and environment friendly technology. Here, we investigated the use of Ag/AgCl-activated carbon (Ag/AgCl-AC) composites in photocatalytic degradation of TDZ under LED light. By the synergic effect of Ag/AgCl and AC, the optimum Ag/carbon weight ratio of 2:1 exhibited superior visible-light photocatalytic activity, the highest removal efficiency was close to 91% in pH 7 matrix. Different types of Ag/AgCl-AC composites were tested, all showed much faster photodegradation kinetics than bare Ag/AgCl in 210min. The degradation products as identified by HPLC-MS revealed that the hydroxylation by hydroxyl radicals and that of oxidation by superoxide radicals as well as holes were the two main pathways for TDZ degradation. Results revealed that the adsorption concentrated TDZ molecules and the photocatalytically generated radicals rapidly degradated TDZ, the two contributions functioned together for removal of the pollutant from water.

Fast Quantitation of Pyrazole Fungicides in Wine by Ambient Ionization Mass Spectrometry

Fungicides are widely used for growing the grapes that are used for making wines. Chromatography coupled with tandem mass spectrometry is usually time and labor consuming for quantitation of fungicides in wines. In this work, a simple ambient mass spectrometry method using paper capillary spray was developed for the fast quantitation of four pyrazole fungicides in wines. Direct analysis of the wine samples was achieved without any sample preparation, obtaining limits of quantitation as low as 2 ng/mL for all four pyrazole fungicides. Quality control experiments also showed adequate accuracy and precision for the analysis of pyrazole fungicides in wine products.

Rapid analysis of forensic-related samples using two ambient ionization techniques coupled to high-resolution mass spectrometers

RATIONALE

This paper highlights the versatility of interfacing two ambient ionization techniques, Laser Diode Thermal Desorption (LDTD) and Atmospheric Solids Analysis Probe (ASAP), to high-resolution mass spectrometers and demonstrate the method's capability to rapidly generate high-quality data from multiple sample types with minimal, if any, sample preparation.

METHODS

For ASAP-MS analysis of solid and liquid samples, the material was transferred to a capillary surface before being introduced into the mass spectrometer. For LDTD-MS analysis, samples were solvent extracted, spotted in a 96-well plate, and the solvent was evaporated before being introduced into the mass spectrometer. All analyses were performed using Atmospheric Pressure Chemical Ionization in positive mode.

RESULTS

Seven consumer "Spice" packets were combined and analyzed by both ASAP and LDTD, which identified 11 synthetic cannabinoids/cathinones by full MS and MS/MS experiments. To further show the usefulness of these techniques, black tar heroin was analyzed, which resulted in the identification of heroin and its impurities (monoacetylmorphine, papaverine, and noscapine). These experiments were performed on the LTQ-Orbitrap to demonstrate the ability to perform both parallel and serial MS and MSⁿ experiments.

CONCLUSIONS

Interfacing LDTD and ASAP to high-resolution mass spectrometers allows for expeditious analysis of a wide range of samples, with minimal or no sample preparation. Both allow for rapid full scan, MS/MS, and/or MSⁿ experiments from a single sample introduction. Published in 2017. This article is a U.S. Government work and is in the public domain in the USA.