Multi-Walled Carbon Nanotubes as Effective Sorbents for Rapid Analysis of Polycyclic Aromatic Hydrocarbons in Edible Oils Using Dispersive Solid-Phase Extraction (d-SPE) and Gas Chromatography—Tandem Mass Spectrometry (GC-MS/MS)

Triazoles in the environment: An update on sample pretreatment and analysis methods

Triazoles, due to their high bactericidal performance, have been widely used in the agricultural, clinical, and chemical industry. However, triazoles have been proven to cause endocrine-toxic and organ impairment in humans as a potentially toxic substance. Besides, because of the improper use and difficulty of degradation, triazoles pesticide residues left in the environment could pose a threat to the environment. Therefore, the rapid, reliable, accurate, and high-sensitivity triazoles analysis methods are significantly essential to effectively monitor their presence in various samples and safeguard human health. This review aims to summarize and update the progress of the pretreatment and analytical methods of triazole fungicides in environmental samples from 2012 to 2024. Common pretreatment methods used to extract and purify targets include simple steps (e.g., protein precipitation and coated blade spray), liquid-liquid extraction, solid-phase extraction, and various microextraction methods such as liquid-phase microextraction and solid-phase microextraction, among others. Detection methods mainly include liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, supercritical fluid chromatography, sensing methods, and capillary electrophoresis. In addition, we elaborate and compare the advantages and disadvantages of different pretreatment and analytical methods, and their development prospects are discussed.

Polycyclic Aromatic Hydrocarbons' Impact on Crops and Occurrence, Sources, and Detection Methods in Food: A Review

Polycyclic aromatic hydrocarbons (PAHs) represent a category of persistent organic pollutants that pose a global concern in the realm of food safety due to their recognized carcinogenic properties in humans. Food can be contaminated with PAHs that are present in water, air, or soil, or during food processing and cooking. The wide and varied sources of PAHs contribute to their persistent contamination of food, leading to their accumulation within these products. As a result, monitoring of the levels of PAHs in food is necessary to guarantee the safety of food products as well as the public health. This review paper attempts to give its readers an overview of the impact of PAHs on crops, their occurrence and sources, and the methodologies employed for the sample preparation and detection of PAHs in food. In addition, possible directions for future research are proposed. The objective is to provide references for the monitoring, prevention, and in-depth exploration of PAHs in food.

Recent Advances in Sample Preparation and Chromatographic/Mass Spectrometric Techniques for Detecting Polycyclic Aromatic Hydrocarbons in Edible Oils: 2010 to Present

Polycyclic aromatic hydrocarbons are considered to be potentially genotoxic and carcinogenic to humans. For non-smoking populations, food is the main source of polycyclic aromatic hydrocarbons exposure. Due to their lipophilic nature, oils and fats rank among the food items with the highest polycyclic aromatic hydrocarbon content. Consequently, the detection of polycyclic aromatic hydrocarbons in edible oils is critical for the promotion of human health. This paper reviews sample pretreatment methods, such as liquid-phase-based extraction methods, adsorbent-based extraction methods, and the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, combined with detection techniques like mass spectrometry and chromatography-based techniques for accurate quantification of polycyclic aromatic hydrocarbons in edible oils since 2010. An overview on the advances of the methods discussed herein, along with a commentary addition of current challenges and prospects, will guide researchers to focus on developing more effective detection methods and control measures to reduce the potential risks and hazards posed by polycyclic aromatic hydrocarbons.

Application of Sorbent-Based Extraction Techniques in Food Analysis

This review presents an outline of the application of the most popular sorbent-based methods in food analysis. Solid-phase extraction (SPE) is discussed based on the analyses of lipids, mycotoxins, pesticide residues, processing contaminants and flavor compounds, whereas solid-phase microextraction (SPME) is discussed having volatile and flavor compounds but also processing contaminants in mind. Apart from these two most popular methods, other techniques, such as stir bar sorptive extraction (SBSE), molecularly imprinted polymers (MIPs), high-capacity sorbent extraction (HCSE), and needle-trap devices (NTD), are outlined. Additionally, novel forms of sorbent-based extraction methods such as thin-film solid-phase microextraction (TF-SPME) are presented. The utility and challenges related to these techniques are discussed in this review. Finally, the directions and need for future studies are addressed.

Development of a safer and improved analytical method for polycyclic aromatic hydrocarbons in creosote products

Polycyclic aromatic hydrocarbons (PAHs) in creosote products used for wood preservation are regulated in Japan. Although the analytical method for this regulation has been stipulated by law, two main problems have been highlighted, namely the use of dichloromethane, a potential carcinogen, as a solvent and inadequate purification. Therefore, an analytical method to solve these problems was developed in this study. Actual creosote-treated wood samples were examined, and it was found that acetone could be used as an alternative solvent. Purification methods using centrifugation, silica gel cartridges, and strong anion exchange (SAX) cartridges were also developed. It was found that the SAX cartridges strongly retained PAHs, and an effective purification method was developed using this phenomenon, in which contaminants were removed by washing with diethyl ether/hexane (1/9 v/v), which could not be achieved with a silica gel cartridge. This strong retention was attributed to cation-π interactions. The analytical method developed in this study yielded good recoveries (81.4-113.0%) with low relative standard deviations (<6.8%), and the limit of quantification (0.02-0.29 µg/g) was significantly lower than the current creosote product regulation. Therefore, this method can safely and effectively extract and purify PAHs from creosote products.

Strategic preparation of porous magnetic molecularly imprinted polymers via a simple and green method for high-performance adsorption and removal of meropenem

In this study, a facile method has been developed to synthesize a novel type of porous magnetic molecularly imprinted polymers (Fe₃O₄-MER-MMIPs) for the selective adsorption and removal of meropenem. The Fe₃O₄-MER-MMIPs, with abundant functional groups and sufficient magnetism for easy separation, are prepared in aqueous solutions. The porous carriers reduce the overall mass of the MMIPs, greatly improving their adsorption capacity per unit mass and optimizing the overall value of the adsorbents. The green preparation conditions, adsorption performance, and physical and chemical properties of Fe₃O₄-MER-MMIPs have been carefully studied. The developed submicron materials exhibit a homogeneous morphology, satisfactory superparamagnetism (60 emu g^-1), large adsorption capacity (11.49 mg g^-1), quick adsorption kinetics (40 min), and good practical implementation in human serum and environmental water. Finally, the protocol developed in this work delivers a green and feasible method for synthesizing highly efficient adsorbents for the specific adsorption and removal of other antibiotics as well.

Screening of new psychoactive substances in human plasma by magnetic solid phase extraction and LC-QTOF-MS

The emergence of new psychoactive substances (NPSs) is an increasing challenge in forensic toxicology. There are many extraction methods in use to isolate NPSs in biological fluids, including protein precipitation (PPT), liquid-liquid extraction (LLE), and solid phase extraction (SPE). However, there is a need to develop an effective extraction method with a short extraction time and low consumption of solvent. To meet these requirements, magnetic solid phase extraction (m-SPE) was attempted to isolate 40 NPSs in human plasma in this study. Forty NPSs (13 synthetic cannabinoids, 13 phenethylamines, 4 tryptamines, 4 other substances, 3 aminoindanes, 2 piperazines, 1 phencyclidine-type substance) were spiked in plasma and analyzed by m-SPE using COOH-functionalized multi-walled carbon nanotubes with magnetic nanoparticles (COOH-mMWCNTs). A liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method was used for screening and identification of 40 target compounds. Method validation including limits of detection, recovery, matrix effect, and precision was performed for all 40 -target compounds. The limits of detection (LOD) of the 40 analytes were between 0.002 and 0.084 mg/L. Extraction recovery ranged from 36.9% to 110.6% (average 87%). Matrix effects ranged from -29.0% (ion suppression) to 9.8% (ion enhancement). Both intra- and inter-day precision values were less than 27.5% (RSD%). The accurate mass of QTOF-MS enabled the identification of analytes by exact monoisotopic mass and isotopic pattern. m-SPE was applied to extract 40 NPSs, and revealed less time-consuming and laborious than conventional SPE. This method proved to be an advantageous procedure to extract NPSs from biological fluids.

Comprehensive Strategy for Sample Preparation for the Analysis of Food Contaminants and Residues by GC-MS/MS: A Review of Recent Research Trends

Food safety and quality have been gaining increasing attention in recent years. Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), a highly sensitive technique, is gradually being preferred to GC-MS in food safety laboratories since it provides a greater degree of separation on contaminants. In the analysis of food contaminants, sample preparation steps are crucial. The extraction of multiple target analytes simultaneously has become a new trend. Thus, multi-residue analytical methods, such as QuEChERs and adsorption extraction, are fast, simple, cheap, effective, robust, and safe. The number of microorganic contaminants has been increasing worldwide in recent years and are considered contaminants of emerging concern. High separation in MS/MS might be, in certain cases, favored to sample preparation selectivity. The ideal sample extraction procedure and purification method should take into account the contaminants of interest. Moreover, these methods should cooperate with high-resolution MS, and other sensitive full scan MSs that can produce a more comprehensive detection of contaminants in foods. In this review, we discuss the most recent trends in preparation methods for highly effective detection and analysis of food contaminants, which can be considered tools in the control of food quality and safety.

Collaborative compounding of metal-organic frameworks for dispersive solid-phase extraction HPLC-MS/MS determination of tetracyclines in honey

Metal-organic frameworks (MOFs), a sort of dispersive solid-phase extraction (d-SPE) material, has shown considerable prospects in the pretreatment of food, biological and other complex samples. Herein, we developed a method for compounding MOFs for d-SPE and trace determination of tetracyclines (TCs) in honey. When the compounding ratio of MIL-101 (Cr), MIL-100 (Fe) and MIL-53 (Al) was 7:1:2, adsorption-extraction was effective. Followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), the limits of detection were 0.073-0.435 ng/g and the limits of quantitation ranged from 0.239 to 1.449 ng/g for oxytetracycline, tetracycline, chlortetracycline and doxycycline. The method was applied to four kinds of honey samples with recoveries from 88.1% to 126.2%. The compounding of MOFs provides a strategy for purification and multi-target extraction from complex food matrices by d-SPE.

Application of diffusive gradients in thin-films for in-situ monitoring of nitrochlorobenzene compounds in aquatic environments

Nitrochlorobenzene compounds (NCBs) are of key interest in environmental monitoring due to their high toxicity. To better understand the presence and fate of NCBs in aquatic environments, an in-situ sampling technique of diffusive gradients in thin films (DGT) based on hydrophilic-lipophilic-balanced (HLB) resin, combined with gas chromatography, was developed to measure four typical NCBs, e.g. meta-chloronitrobenzene (MNCB), para-chloronitrobenzene (PNCB), ortho-chloronitrobenzene (ONCB), and 2,4-dinitrochlorobenzene (CDNB). The diffusion coefficients of MNCB, PNCB, ONCB, and CDNB in agarose-based gel were firstly determined in diffusion cell experiments and ranged from 7.19 × 10^-6 to 7.49 × 10^-6 cm/s. The capacities of HLB-DGT for MNCB, PNCB, ONCB, and CDNB were higher than 114.65, 117.52, 117.72, and 37.58 μg/cm², respectively. The HLB-DGT performance on NCBs determination was demonstrated to be independent of natural fluctuations in pH (3-9), ionic strength (0.001-0.5 M), and dissolved organic matter concentrations (0-20 mg/L) and of deployment time (0-120 h). In the field application, the DGT-based method to measure NCBs not only proved to be accurate and effective, but also performed better than the grab sampling method under the variable conditions. This study demonstrates that the newly developed in-situ method based on DGT can provide an attractive alternative for the routine monitoring of NCBs in aquatic environments.

Carboxylated Multiwalled Carbon Nanotubes as Dispersive Solid-Phase Extraction Sorbent to Determine Eighteen Polychlorinated Biphenyls in Vegetable Samples by Gas Chromatography-Mass Spectrometry

A simple, rapid, and reliable method based on dispersive solid-phase extraction (d-SPE) and gas chromatography-mass spectrometry (GC-MS) was developed for quantitating polychlorinated biphenyls (PCBs) in vegetable samples. Parameters affecting both the extraction yields and cleanup efficiency, including the type and volume of extraction solvent, extraction time, type and volume of cleanup sorbent, and cleanup time, were optimized. Matrix effects were evaluated, and matrix-matched calibration was recommended. Under the optimized conditions, carboxylated multiwalled carbon nanotubes (MWCNTs-COOH), which exhibit excellent adsorption capabilities due to large surface area and unique structure, were employed as d-SPE sorbent to remove interfering substances, rather than the analytes, from vegetable samples. Satisfactory linear relationship was observed for all PCBs across a concentration range of 5-500 μg/kg with correlation coefficients no less than 0.9993. Four representative vegetables (cucumber, tomato, lettuce, and cabbage) were selected as matrices for method validation. Each matrix was spiked at concentrations of 5, 10, and 100 μg/kg to evaluate recoveries, which ranged from 84.5% to 116.5% with relative standard deviations (n=6) between 0.6% and 17.6%. The limits of detection and the limits of quantification ranged from 0.3 to 1.4 μg/kg and 0.8 to 4.5 μg/kg, respectively. Twelve real vegetable samples were analyzed using the proposed method. Three of the target PCBs were detected in one lettuce sample with the total concentration of 17.9 μg/kg.