A multiresidue method using ion-trap gas chromatography?tandem mass spectrometry with or without derivatisation with pentafluorobenzylbromide for the analysis of pesticides in the atmosphere

Molecularly imprinted dispersive micro solid-phase extraction and tandem derivatization for the determination of histamine in fermented wines

Histamine causes allergic reactions and can serve as an indicator for assessing food quality. This study designed and developed a dispersive micro solid-phase extraction (D-μSPE) method that combined the advantages of dispersive liquid-liquid extraction and solid-phase extraction (SPE). Molecularly imprinted polymers (MIPs) were employed as the solid phase in the D-μSPE method to extract histamine in wine samples. We used microwave energy to significantly reduce the synthesis time, achieving an 11.1-fold shorter synthesis time compared to the conventional MIP synthetic method. Under optimized D-μSPE conditions, our results showed that the dispersive solvent could effectively increase the adsorption performance of MIPs in wine samples by 97.7%. To improve the sensitivity of histamine detection in gas chromatography-mass spectrometry, we employed the microwave-assisted tandem derivatization method to reuse excess derivatization reagents and reduce energy consumption and reaction time. Calibration curves were constructed for wine samples spiked with 0-400 nmol histamine using the standard addition method, resulting in good linearity with a coefficient of determination of 0.999. The intra- and inter-batch relative standard deviations of the slope and intercept were < 0.7% and < 5.3%, respectively. The limits of quantitation and detection were 0.4 nmol and 0.1 nmol, respectively. The developed method was successfully applied to analyze the histamine concentration in 10 commercial wine samples. In addition, the AGREEprep tool was used to evaluate the greenness performance of the developed method, which obtained a higher score than the other reported methods.

Airborne Pesticides-Deep Diving into Sampling and Analysis

The escalating utilization of pesticides has led to pronounced environmental contamination, posing a significant threat to agroecosystems. The extensive and persistent global application of these chemicals has been linked to a spectrum of acute and chronic human health concerns. This review paper focuses on the concentrations of airborne pesticides in both indoor and outdoor environments. The collection of diverse pesticide compounds from the atmosphere is examined, with a particular emphasis on active and passive air sampling techniques. Furthermore, a critical evaluation is conducted on the methodologies employed for the extraction and subsequent quantification of airborne pesticides. This analysis takes into consideration the complexities involved in ensuring accurate measurements, highlighting the advancements and limitations of current practices. By synthesizing these aspects, this review aims to foster a more comprehensive and informed comprehension of the intricate dynamics related to the presence and measurement of airborne pesticides. This, in turn, is poised to significantly contribute to the refinement of environmental monitoring strategies and the augmentation of precise risk assessments.

Application of XAD-2 resin-based passive samplers and SPME-GC-MS/MS analysis for the monitoring of spatial and temporal variations of atmospheric pesticides in Luxembourg

Passive air sampling has been shown to be a very interesting alternative to high-volume sampling by overcoming its disadvantages (size, weight, expensiveness). However, to date, only limited data is available about passive air sampling of current-use pesticides. In order to test if passive samplers allow monitoring of spatial and temporal variations of atmospheric pesticide concentrations, five XAD-2-resin based passive air samplers were deployed at five locations in Luxembourg. Samplers were analyzed using accelerated solvent extraction coupled to solid-phase microextraction and gas chromatography with tandem mass spectrometry. Collected data was used to study the spatial and temporal variations of the concentrations of the compounds. Twenty two pesticides were detected between March and October, while no pesticides were detected from November to February. Highest concentrations were measured on the rural sites, suggesting that the used XAD-2 resin-based passive samplers allow the simultaneous monitoring of multiple current-use pesticides and identifying spatial and temporal variations.

Temporal variations of concentrations of currently used pesticides in the atmosphere of Strasbourg, France

Atmospheric samples have been collected in Strasbourg between April 18 and May 29, 2007 and were analyzed for 71 current-use pesticides, of which 38 were detected. Average concentrations ranged from 0.09 ng m(-3) for Fenarimol to 110.42 ng m(-3) for Dimethachlor, which was slightly higher than the concentrations reported from other, comparable agricultural regions. Significant temporal variations were observed for 30 pesticides, and for most of them it could be shown that these were linked to time, temperature or atmospheric pressure. In several cases this helped to identify pesticide application just before or at the beginning of the sampling period, or ongoing treatment. Humidity, in contrast to previous reports, could not be linked to these variations. For the other 8 pesticides, only very little temporal variations were observed. Generally, these concentrations were low (less than 1 ng m(-3)), and it was assumed that they are not in use in Alsace at present.

Comparison of the efficiencies of different types of adsorbents at trapping currently used pesticides in the gaseous phase using the technique of high-volume sampling

Atmospheric samples were collected in an urban area (Strasbourg centre) in spring/summer 2004, in order to determine the concentrations of different pesticides in the gaseous and particulate phases and to compare the efficiencies of different adsorbents at trapping the gaseous phase. Two high-volume samplers were placed next to each other in the botanical garden in the centre of Strasbourg. Air sampling was carried out using a glass fibre filter and different adsorbents for 48 hrs. The following adsorbents and combinations of adsorbents were compared: XAD-2 with PUF, XAD4 with PUF, XAD-2 with a PUF-XAD2-PUF sandwich, PUF with a PUF-XAD4-PUF sandwich. In order of efficiency at trapping pesticides, the "sandwiches" are the most efficient, followed by XAD-2 and XAD-4 resins. However, although the "sandwiches" are slightly better at trapping than XAD-2, the use of XAD-2 is recommended for technical reasons. The PUFs are the least efficient at trapping. Among the 27 pesticides analysed, trifluralin, alachlor, metolachlor and captan were the most concentrated pesticides, followed by lindane, alpha-endosulfan and diflufenican. This result is in accordance with farming activity in the Alsace region, where the pesticides that are used on large crops (maize, cereals) are applied in the greatest quantities. Vineyards are another important form of agriculture in Alsace, but the quantities of pesticides applied in comparison to those used on large crops is very low, which explains the low detection of vineyard pesticides in air samples observed here. The concentrations are depend on the identities and properties of the pesticides analysed, but on the whole they remain rather low. It is important to perform measurements like these in the urban environment, as these compounds can be harmful to human health and the environment and so their concentrations need to be monitored.

Study of different parameters affecting the derivatization of acidic herbicides with trimethylsulfonium hydroxide to make them suitable for gas chromatography analysis

In this study, an orthogonal array design was applied to know the way different parameters affected the derivatization of some herbicides that are commonly applied in the soils. Herbicides formulated as esters have been reported to rapidly hydrolyse, in contact with soil, to their corresponding acids and phenols. What involves is that both forms need to be monitored. Acidic herbicides and phenols cannot be detected by gas chromatography (GC) due to their polarity and low volatility that cause peak asymmetry. Therefore, masking of these polar groups by eliminating the active hydrogen atom with derivatization to their corresponding esters/ethers is needed in order to yield products that possess enhanced volatility and improved GC properties. A lot of derivatization reagents have been proposed but trimethylsulfonium hydroxide (TMSH) was selected due to its easy and quantitative formation of methyl esters/ethers. It was observed that the addition of TMSH promoted not only esterification of acids/phenols but trans-esterification of the original non-hydrolyzed remaining esters to their corresponding methyl ones. As a result, methyl esters/ethers were the final product of both reactions. Different parameters were studied in the statistical design for both TMSH promoted reactions: type of solvent, pH, temperature and time of incubation. The amount of derivatization reagent was calculated to be high enough to ensure the complete derivatization of all compounds present in the sample. The reaction medium was shown as an important factor. The formation of some methyl esters/ethers decreased with increasing time and temperature because trans-esterification, being an equilibrium where the formation of smaller structures is promoted, was not enough shifted. However, the statistical analysis revealed that only the pH of the solution played an important role during the derivatization process. The presence of the anionic form of the acids appeared to be essential for derivatization, being diminished in strong acidic conditions. In addition, pre-heating was shown not to improve derivatization reaction, being easily carried on in the injector port of the GC system.

Analysis of trace levels of pesticides in rainwater using SPME and GC–tandem mass spectrometry

A multiresidue method using gas chromatography coupled to ion trap tandem mass spectrometry (GC-ITD-MS/MS) associated with solid phase microextraction (SPME) was developed for the analysis of 20 pesticides commonly used in the Alsace region in rainwater samples. Since the pesticides were expected to be present at very low concentrations and in complex matrices, the analytical method used was both highly selective and sensitive. Therefore, fibers coated with polyacrylate (PA), polydimethylsiloxane (PDMS) and polydimethylsiloxane-divinylbenzene (PDMS-DVB) were tested, and the parameters affecting the precision and accuracy of the SPME method were investigated and optimized. These parameters include the type of fiber, the adsorption time, the effect of salt, and the extraction temperature. The PDMS fiber was the most polyvalent for the extractions of the different pesticides studied. Detection limits of between 5 and 500 ng L(-1), depending on the compounds under study (except for those which could not be analyzed: captan and mevinphos), were obtained with this analytical procedure. This method was applied to the analysis of rainwater samples collected simultaneously on a weekly basis at one rural and one urban site between March 2002 and July 2003. While some of the 20 pesticides analyzed were constantly detected (such as lindane and atrazine), a strong temporal variability was observed for some of the others (including alachlor, metolachlor, atrazine).