Determination of Antibiotics in Vegetables Using QuEChERS-Based Method and Liquid Chromatography-Quadrupole Linear Ion Trap Mass Spectrometry

Facile preparation of hollow covalent organic frameworks as superior and universal matrix clean-up micro-structures for high throughout determination of food hazards

The complicated food matrix seriously limits the one-time test for the potential food hazards in non-targeted analysis. Accordingly, developing advanced sample pretreatment strategy to reduce matrix effects is of great significance. Herein, newly-integrated hollow-structured covalent organic frameworks (HCOFs) with large internal adsorption capacity and target-matched pore size were synthesized via etching the core-shell structured COFs. The as-prepared HCOFs could be directly applied for matrix clean-up of vegetable samples, while further modification of polydopamine (PDA) network facilitated application for animal samples. Both HCOFs and HCOFs@PDA with the comparable sizes to the matrix interference gave excellent adsorption performance to targets, achieving satisfied recoveries (70%-120%) toward 90 pesticides and 44 veterinary drugs in one-test, respectively. This work showed the great potential of the facile-integrated HCOFs with high stability and customized size to remove interference matrix and offered a universal strategy to achieve simultaneous screening of hazards with considerable quantity in high-throughput non-targeted analysis.

Liquid-liquid and solid-liquid extractions with low-temperature partitioning - A review

The paper represents the first review of solvent extraction techniques utilizing the low-temperature partitioning/purification (LTP) approach. Initially conceived in the 1960s to purify extracts from fatty matrices, it wasn't until the 2000s that this approach received increasing attention for its efficacy in extracting organic compounds from diverse samples, often without additional cleanup steps. This review covers a brief history and proposes a mechanism for LTP-based solvent extraction. Furthermore, the principal practical issues of the technique are spotlighted, elucidating the factors influencing extraction efficiency. The advantages, limitations, and potential combinations with other extraction techniques of the LTP-based solvent extractions are analyzed. The versatility of the LTP approach is demonstrated by its applications in extracting various compounds from food, environmental, and biological samples, emphasizing its potential for rapid sample preparation with minimal steps, few chemicals, and minimal analyst intervention.

Multitarget and suspect-screening of antimicrobials in vegetables samples: Uptake experiments and identification of transformation products

This work provided an accurate analytical method to perform a multitarget analysis of a variety of antimicrobials (AMs) including sulfonamides, tetracyclines, macrolides, fluoroquinolones and quinolones, one imidazole and one nitroimidazole, one triazole, one diaminopyridine and one derivative of Penicillium stoloniferum in vegetables. The analysis is performed using liquid-chromatography coupled to a low-resolution triple quadrupole mass spectrometer (UHPLC-MS/MS) to detect the target analytesor coupled to a high-resolution q-Orbitrap (HRMS) to monitor the formed transformation products (TPs). Both instruments were compared in terms of limits of quantification and matrix effect at the detection. The method was applied to determine the presence of AMs in organic and non-organic vegetables, where sulfadiazine and mycophenolic acid were detected. On the other hand, the transference of four AMs (trimethoprim, sulfamethazine, enrofloxacin, and chlortetracycline) from soils to lettuces was evaluated through controlled uptake experiments. The choice of AMs was based on the classification into different families, and on the fact that those AM families are the most frequently detected in the environment. In this case, each of the AMs with which the soils were contaminated were found in the exposed lettuces. Moreover, in both studies, specific TPs of the AMs were identified, posing the necessity of assessing their effects in relation to food and human safety.

Optimization and validation of multiresidual extraction methods for pharmaceuticals in Soil, Lettuce, and Earthworms

The presence of human and veterinary pharmaceuticals (PhACs) in the environment poses potential risks. To comprehensively assess these risks, robust multiresidual analytical methods are essential for determining a broad spectrum of PhAC classes in various environmental compartments (soil, plants, and soil organisms). This study optimized extraction methods for analyzing over 40 PhACs from various matrices, including soil, lettuce, and earthworms. A four-step ultrasonic extraction method with varying extraction conditions and subsequent solid phase extraction was developed for soil samples. QuEChERS methods were optimized for extracting PhACs from lettuce and earthworm samples, addressing a literature gap in these less-studied matrices. The quantification of PhACs in soil, lettuce, and earthworm extracts was performed using a single LC-MS/MS method. Following thorough method validation, earthworms and lettuce were exposed to a mixture of 27 pharmaceuticals in a soil environment. The method validation results demonstrated the robustness of these methods for a broad spectrum of PhACs. Specifically, 29 out of 42 PhACs were extracted with an average efficiency > 50% and RSD < 30% from the soil; 40 out of 42 PhACs exhibited average efficiency > 50% and %RSD < 30% from the earthworms, while 39 out of 42 PhACs showed average efficiency > 50% and RSD < 30% from the lettuce. Exposure experiments confirmed the viability of these methods for quantifying a diverse range of PhACs in different environmental compartments. This study presents three thoroughly validated methods for determining more than 40 PhACs in diverse matrices, enabling a comprehensive assessment of PhAC dissemination in the environment.

Investigation of the spatial distribution of airborne polycyclic aromatic hydrocarbons using Rhytidiadelphus squarrosus in Tórshavn, Faroe Islands

Due to adverse effects of Polycyclic Aromatic Hydrocarbons (PAHs) on human health, it is important to understand how airborne PAHs, are spatially distributed within urban areas. Moss has been shown to be a suitable material for biomonitoring of airborne PAH pollution. In this study, the moss Rhytidiadelphus squarrosus was sampled throughout Tórshavn, Faroe Islands. 53 Rhytidiadelphus squarrosus samples were extracted using a matrix solid-phase dispersive extraction method and analysed for 19 parent PAHs and six groups of alkylated PAHs using gas chromatography mass-spectrometry. All PAHs were quantified in at least one Rhytidiadelphus squarrosus sample, and the sum of the EPA 16 PAHs (ƩPAHEPA16) ranged from 0.90 to 344 µg kg-1 dry weight. Higher concentrations were found close to the harbour and the main roads. The spatial correlation was investigated for the ƩPAHEPA16, pyrene, fluoranthene, chrysene, benzo(e)pyrene, benzo(g,h,i)perylene, C1-phenanthrenes/C1-anthracenes, and C2-phenanthrenes/C2-anthracenes using variograms. The effective range of the spatial correlation was between 500 to 700 m of all PAHs. The evaluation of diagnostic ratios of fluoranthene to pyrene, and benzo(a)anthracene to chrysene suggest that different pollution sources affect urban areas of different types. To the best of our knowledge, this is the first time airborne PAH pollution patterns were mapped in an Arctic town, and the first time, Rhytidiadelphus squarrosus was used for tracing PAH pollution sources. Rhytidiadelphus squarrosus is suitable for biomonitoring and mapping PAH pollution within urban areas since it is widespread, and suitable for mapping PAHs.

Comparison of conventional and dispersive solid phase extraction clean-up approaches for the simultaneous analysis of tetracyclines and sulfonamides in a variety of fresh vegetables

The extensive use of antibiotics in agriculture has led to the occurrence of residual drugs in different vegetables frequently consumed by humans. This could pose a potential threat to human health, not only because of the possible effects after ingestion but also because the transmission of antibiotic-resistant genes could occur. In this work, two accurate sample preparation procedures were developed and validated for the simultaneous analysis of sulfonamides (SAs) and tetracyclines (TCs) in four of the most widely consumed vegetables (lettuce, onion, tomato, and carrot) in Europe. The evaluated protocols were based on QuECHERS for extraction and subsequent clean-up by SPE (solid phase extraction) or dispersive SPE. Parameters affecting both extraction and clean-up were carefully evaluated and selected for accuracy of results and minimal matrix effect. Overall, apparent recoveries were above 70% for most of the target analytes with both analytical procedures, and adequate precision (RSD<30%) was obtained for all the matrices. The procedural limits of quantification (LOQPRO) values for SPE clean-up remained below 4.4 μg kg-1 for TCs in all vegetables except for chlortetracycline (CTC) in lettuce (11.3 μg kg-1) and 3.0 μg kg-1 for SAs, with the exception of sulfadiazine (SDZ) in onion (3.9 μg kg-1) and sulfathiazole (STZ) in carrot (5.0 μg kg-1). Lower LOQPRO values (0.1-3.7 μg kg-1) were obtained, in general, when dSPE clean-up was employed. Both methods were applied to twenty-five market vegetable samples from ecological and conventional agriculture and only sulfamethazine (SMZ) and sulfapyridine (SPD) were detected in lettuce at 1.2 μg kg-1 and 0.5 μg kg-1, respectively.

Quantitative Modeling of the Degradation of Pesticide Residues in Wheat Flour Supply Chain

Pesticide residues in grain products are a major issue due to their comprehensive and long-term impact on human health, and quantitative modeling on the degradation of pesticide residues facilitate the prediction of pesticide residue level with time during storage. Herein, we tried to study the effect of temperature and relative humidity on the degradation profiles of five pesticides (carbendazim, bensulfuron methyl, triazophos, chlorpyrifos, and carbosulfan) in wheat and flour and establish quantitative models for prediction purpose. Positive samples were prepared by spraying the corresponding pesticide standards of certain concentrations. Then, these positive samples were stored at different combinations of temperatures (20 °C, 30 °C, 40 °C, 50 °C) and relative humidity (50%, 60%, 70%, 80%). Samples were collected at specific time points, ground, and the pesticide residues were extracted and purified by using QuEChERS method, and then quantified by using UPLC-MS/MS. Quantitative model of pesticide residues was constructed using Minitab 17 software. Results showed that high temperature and high relative humidity accelerate the degradation of the five pesticide residues, and their degradation profiles and half-lives over temperature and relative humidity varied among pesticides. The quantitative model for pesticide degradation in the whole process from wheat to flour was constructed, with R² above 0.817 for wheat and 0.796 for flour, respectively. The quantitative model allows the prediction of the pesticide residual level in the process from wheat to flour.

Green and Efficient Determination of Fluoroquinolone Residues in Edible Green Fruits and Leafy Vegetables by Ultrasound-Assisted Extraction Followed by HPLC-MS/MS

In this work, a simple, quick and efficient analytical method for determination of human and veterinary fluoroquinolone antimicrobial residues in lettuce, cucumber and spinach is developed. The procedure entails a 6 min ultrasound-assisted extraction (UAE, 3 × 2 min) in an alkaline (2% v/v NH₃) aqueous solution containing Mg²⁺ ions (3 × 6 mL), with no need for organic solvents. The extract is submitted to cleanup on the HLB™ cartridge and the fluoroquinolones are separated and quantified by HPLC-MS/MS in a 10 min chromatographic run, using a small amount of acetonitrile in the mobile phase. The method, entirely developed in real matrices, is validated according to the updated analytical guidelines and provided suitable recoveries in the range of 67–116% and precision (RSD ≤ 20%, n = 3) at different concentrations (15, 70 and 150 ng g⁻¹), with method quantification limits of 2–10 ng g⁻¹. Fluoroquinolones were detected and quantified at concentrations from few to hundreds of nanograms per gram in vegetables from supermarkets, demonstrating the applicability of the method for monitoring residues of these pharmaceuticals.

Novel and simple analytical method for simultaneous determination of sulfonamide, quinolone, tetracycline, macrolide, and chloramphenicol antibiotics in soil

The multiclass determination of antibiotic residues in the soil is challenging because of its complex physicochemical properties. In this study, a simple analytical method was developed to simultaneously extract and determine 58 antibiotics from the soil. A novel acidity-regulated extraction-partition-concentration protocol was established for the simultaneous extraction of five classes (23 sulfonamides, 18 quinolones, five tetracyclines, eight macrolides, and four chloramphenicols) of antibiotics from the soil. Compared to traditional methods, the sample preparation efficiency was significantly improved by four times (45 min vs. 230 min) by optimizing the extraction method and omitting the time-consuming solid-phase extraction (SPE) procedure. The ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was optimized to determine the 58 antibiotics in a single run by applying positive/negative switching acquisition mode in less than 10 min with the baseline separation of sulfameter and sulfamethoxypyridazine. Suitable recoveries, ranging between 60 and 120%, were obtained for most antibiotics, with RSD <20%. The limits of quantification (LOQ) of the method were 2 μg/kg and 5 μg/kg. Thus, this study provides a simple, reliable, and economical method for accurately and rapidly determining a multiclass of antibiotics in the soil.

Enantioselective separation, analysis and stereoselective dissipation of the chiral pesticide cloquintocet-mexyl using a modified QuEChERS method by high-performance liquid chromatography tandem mass spectrometry

An efficient and novel enantioseparation method was successfully developed and validated to quantify the enantiomers of cloquintocet-mexyl in soil, millet, enoki mushroom, oilseed rape, and watermelon using a modified QuEChERS technique combined with HPLC-MS/MS. This method showed reliable performances for determining both enantiomers of cloquintocet-mexyl in all five matrices. The limits of detection and limits of quantification were in the range of 0.06-0.15 μg kg^-1 and 0.2-0.5 μg kg^-1, respectively. Good linearities were obtained with correlation coefficients ≥0.9954. The mean recoveries were between 84.1% and 111.5%, with relative standard deviations ranging from 1.2% to 9.8% at three spiked levels. Additionally, the study of stereoselective dissipation of cloquintocet-mexyl in soil indicated that (R)-cloquintocet-mexyl was preferentially degraded. This work is the first to describe a chiral analytical method and enantioselective behavior of cloquintocet-mexyl and provide basic data for the risk evaluation of cloquintocet-mexyl in food and environmental safety.

Determination of multiple antibiotics in agricultural soil using a quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry

In this study, we combined ultra-high performance liquid chromatography with tandem mass spectrometry to establish a quick, easy, cheap, effective, rugged, and safe method of detecting 21 target antibiotics in agricultural soil samples. Antibiotics were extracted with mixed solvents consisting of ethylenediaminetetraacetic acid disodium salt dihydrate and phosphoric acid citric acid buffer and acetonitrile which were purified with octadecylsilyl as an adsorbent and anhydrous sodium sulfate as a desiccant. This method was able to effectively extract all of the target antibiotics from agricultural soils, with recovery efficiencies ranging from 55 to 108% and limits of detection between 0.09-0.68 μg/kg. We also validated this new method for selectivity, sensitivity, and reliability of detecting multiple antibiotics in 12 samples. Considering the potential environmental and public health effects of antibiotics in agricultural soils, our new method can help analyze the degree of antibiotic contamination and provide valuable information for soil quality and risk assessment.

The pesticide residue analysis in commodities with high content of chlorophyll based on the quick, easy, cheap, effective, rugged, and safe method: A review

In multiresidue analysis, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) is one of the most popular techniques routinely used by researchers during pesticide analysis of food and vegetable samples. Originally, the QuEChERS method was developed for analysis of pesticide residues from fruits and vegetables, but rapidly gained popularity in the extraction of analytes from different matrices. This analytical approach shows several advantages over traditional extraction techniques: it requires lower sample and solvent amounts while shortening the time of sample preparation. However, it presents some limitations for complex matrices such as those containing high amounts of chlorophyll. To overcome the problem of strong matrix effect and influence of interferences, different approaches are applied. Most are concerning modifications of the cleanup step, that is, sorbent type and its amount. Optimization of other parameters, such as sample size, hydration level, extraction solvent, and buffering, also has an impact on overall performance. Combining proper sample preparation with modern highly sensitive and selective detection techniques enables receiving desired limits of quantification. This article presents an overview of strategies employed by researchers for analysis of green, high chlorophyll content commodities and results obtained in their studies.

Application of a fast and sensitive method for the determination of contaminants of emerging concern in wastewater using a quick, easy, cheap, effective, rugged and safe-based extraction and liquid chromatography coupled to mass spectrometry

The inefficiency of wastewater treatment plants (WWTPs) to remove contaminants of emerging concern (CECs) leads to their continuous release to the environment. Consequently, CECs are present at low concentrations in the treated wastewater (TWW), producing unpredicted and unwanted effects on living organisms as they are discharged into water receiving bodies. This work presents a fast and reliable method for the determination of CECs in TWW based on the innovative application of a QuEChERS (quick, easy, cheap, effective, rugged and safe) method for water extraction and determination by sensitive liquid chromatography coupled to quadrupole-linear ion trap tandem mass spectrometry (LC-QqLIT-MS/MS). The scope of the proposed QuEChERS-based method allows the monitoring of 107 CECs, including pharmaceuticals (58), antibiotics (16) and pesticides (33). The proposed method was successfully validated in urban TWW at two concentration levels (50 and 500 ng L^-1) and it is a feasible alternative to conventional and time-consuming solid-phase extraction (SPE) methodologies. 89% of the CECs presented mean recovery values in the 70-120% range with relative standard deviations (RSDs) always < 20% (intra and inter-day precision), and limits of quantification (LOQs) in the range 5-500 ng L^-1 (89% of the compounds showed a LOQ ≤ 50 ng L^-1). The applicability of the method was demonstrated by the analysis of urban TWW samples (7 sampling events). In total, 35 CECs (23 pharmaceuticals, 2 antibiotics and 10 pesticides) were detected in the monitored samples with concentrations ranging from 5 to 677 ng L^-1.

QuEChERS LC-MS/MS Screening Method for Mycotoxin Detection in Cereal Products and Spices

We developed and validated a screening method for mycotoxin analysis in cereal products and spices. Ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was used for the analysis. Dispersive solid-phase extractions (d-SPEs) were used for the extraction of samples. Ochratoxin A (OTA), zearalenone (ZEA), aflatoxins (AFLA; AFB1, AFB2, AFG1, AFG2), deoxynivalenol (DON), fumonisin (FUMO; FB1, FB2, FB3), T2, and HT2 were validated in maize. AFLA and DON were validated in black pepper. The method satisfies the requirements of Commission Regulation (EC) no. 401/2006 and (EC) no. 1881/2006. The screening target concentration (STC) was under maximum permitted levels (MLs) for all mycotoxins validated. The method's performance was assessed by two different proficiencies and tested with 100 real samples.

Trace analysis of 28 antibiotics in plant tissues (root, stem, leaf and seed) by optimized QuEChERS pretreatment with UHPLC-MS/MS detection

Phytoremediation has proven to be an effective in-situ treatment technique for antibiotic contamination. Due to the immature methods of extracting multi-antibiotics in different plant tissues, the antibiotic absorption and transportation mechanism in the phytoremediation process has yet to be resolved. Therefore, an improved Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) pretreatment with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection method for 28 antibiotics in different plant tissues (root, stem, leaf and seed) was developed in this study. The optimized method showed satisfactory performance with recoveries for most antibiotics ranging from 70% to 130% (except sulfadoxine with 138 ± 8.84% in root, sulfameter with 68.9 ± 1.87% and sulfadoxine with 141 ± 10.0% in seed). The limits of detection (LODs) of the target compounds in root, stem, leaf and seed were 0.04 ± 0.02 ~ 2.50 ± 1.14 ng/g, 0.05 ± 0.02 ~ 1.78 ± 0.42 ng/g, 0.06 ± 0.01 ~ 2.50 ± 0.14 ng/g and 0.13 ± 0.10 ~ 3.64 ± 0.74 ng/g, respectively. This developed method was successfully applied to the determination of antibiotics in different tissues of hydroponic wetland plants exposed to antibiotics-spiked water for one-month. Sixteen of 28 spiked antibiotics were detected in plant tissue samples. Overall, of these 16 antibiotics, all were detected in root samples (from < LOQ to 1478 ± 353 ng/g), eleven in stem samples (from < LOQ to 425 ± 47.0 ng/g), and nine in leaf samples (from < LOQ to 429 ± 84.5 ng/g). This developed analytical method provided a robust tool for the simultaneous screening and determination of antibiotics in different plant tissues.

Comparison of high resolution mrm and sequential window acquisition of all theoretical fragment-ion acquisition modes for the quantitation of 48 wastewater-borne pollutants in lettuce

Screening of a large number of chemicals of emerging concern is highly desirable for the control of crops irrigated with reclaimed water since it is considered an alternative water source of great value. This study describes a high resolution mass spectrometry approach for developing methods for quantification in lettuce leaves of 48 different wastewater-borne pollutants (including analgesics and anti-inflammatories, anti-hypertensives, antifungal agents, lipid regulators, psychiatric drugs and stimulants, β-blockers, antibiotics, antimycotics, and sweeteners) frequently found in water resources. In this respect, a simple and fast QuEChERS-based method for the determination of contaminants in lettuce has been developed. During extraction, the use of formic acid was adopted to further improve the results of some problematic compounds (e.g., fenofibrate, furosemide, metronidazole, oxcarbazepine, sulfanilamide). High resolution multiple reaction monitoring (MRMHR) and SWATH acquisition were compared in term of accuracy, repeatability, sensitivity, linearity and matrix effect. Both methods provided similar recoveries between 80 and 120% in lettuce leaves, although sulfanilamide, ciprofloxacin, and sulfamethazine presenting values of 26.8, 27.8, and 28.4% in MRMHR and 25, 33.9, and 35% in SWATH, respectively. The effectiveness of a two-step cleanup on analyte recovery was also assessed and matrix effects were also taken into consideration during the method validation. The developed method allows the simultaneous quantitative analysis of 48 compounds (drug residues and metabolites) in lettuce leaves irrigated with treated wastewater for human consumption. Application of the present method to lettuce crops growth in controlled conditions showed the presence of 14 out 48 studied compounds with similar concentrations in both acquisition modes ranging from 3.3 and 1.3 ng g - 1 for climbazole (for MRMHR and SWATH, respectively) to 33.2 and 17.7 ng g - 1 for sulfamethazine. Drug residues such as carbamazepine (6.0 and 8.5 ng g - 1), and its metabolite carbamazepine epoxide (18.1 and 16.5 ng g - 1), frequently found in wastewater effluents, were also detected.

A review of pretreatment and analysis of macrolides in food (Update Since 2010)

Macrolides are versatile broad-spectrum antibiotics whose activity stems from the presence of a macrolide ring. They are widely used in veterinary medicine to prevent and treat disease. However, because of their improper use and the absence of effective regulation, these compounds pose a threat to human health and the environment. Consequently, simple, quick, economical, and effective techniques are required to analyze macrolides in animal-derived foods, biological samples, and environmental samples. This paper presents a comprehensive overview of the pretreatment and analytical methods used for macrolides in various sample matrices, focusing on the developments since 2010. Pretreatment methods mainly include liquid-liquid extraction, solid-phase extraction, matrix solid-phase dispersion, and microextraction methods. Detection and quantification methods mainly include liquid chromatography (coupled to mass spectrometry or other detectors), electrochemical methods, capillary electrophoresis, and immunoassays. Furthermore, a comparison between the pros and cons of these methods and prospects for future developments are also discussed.

Electrooxidation of tetracycline antibiotic demeclocycline at unmodified boron-doped diamond electrode and its enhancement determination in surfactant-containing media

In this paper, for the first time, the study of voltammetric determination of tetracycline antibiotic demeclocycline was conducted. The oxidation of compound was investigated using a commercially available boron-doped diamond electrode pretreated electrochemically (anodic and subsequent cathodic). Addition of anionic surfactant, sodium dodecylsulfate (SDS) and cationic surfactant, cetyltrimethylammonium bromide (CTAB) to the demeclocycline-containing electrolyte solution at pH 2.0 and 9.0, respectively, was found to improve the sensitivity of the stripping voltammetric measurements. Employing square-wave stripping mode (after 30 s accumulation at open-circuit condition) in Britton-Robinson buffer, the limits of detection were found to be 1.17 μg mL^-1 (2.3 × 10^-6 M) for 4 × 10^-4 SDS-containing buffer solution at pH 2, and 0.24 μg mL^-1 (4.8 × 10^-7 M) for 1 × 10^-4 CTAB-containing buffer solution at pH 9.0. The feasibility of the developed approach for the quantification of demeclocycline was tested in urine samples.

Trends in sensitive detection and rapid removal of sulfonamides: A review

Sulfonamides in environmental water, food, and feed are a major concern for both aquatic ecosystems and public health, because they may lead to the health risk of drug resistance. Thus, numerous sensitive detection and rapid removal methodologies have been established. This review summarizes the sample preparation techniques and instrumental methods used for sensitive detection of sulfonamides. Additionally, adsorption and photocatalysis for the rapid removal of sulfonamides are also discussed. This review provides a comprehensive perspective on future sulfonamide analyses that have good performance, and on the basic methods for the rapid removal of sulfonamides.

Quantification and confirmation of four aflatoxins using a LC-MS/MS QTRAP system in multiple reaction monitoring, enhanced product ion scan, and MS3 modes

A simple, rapid, and efficient liquid chromatography tandem mass spectrometry (LC-MS/MS) method, operated in electrospray ionization and quadrupole linear ion trap modes, has been developed for the identification and structural characterization of aflatoxins in peanuts and its derivative products or bean sauce. Samples (5 g) were extracted with acetonitrile/water/formic acid (79:20:1, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/0.2% formic acid) and analyzed by UPLC-MS/MS. External calibration was used for qualification. The developed multiple reaction monitoring-information-dependent acquisition-enhanced product ion method enabled quantification and confirmation of the analytes in a single run. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis. An in-house library was constructed for identification. Calibration curves showed good linearity with correlation coefficients (r) higher than 0.994. Limits of detection were determined to be below 0.26 µg kg^-1 for most analytes. The recoveries for those substances were in the acceptable range of 80.2%-119.1%. A new LC-MS³ method was established for further confirmation. One pickled pepper peanut was found to contain aflatoxins B1, B2, and G1 with contents of 90.93, 26.64, and 1.92 µg kg^-1, respectively.

Antibiotic Residues in Food: Extraction, Analysis, and Human Health Concerns

The abundant use of antibiotics leads to antibiotic residues in frequently consumed foods. Residual antibiotics in food may have adverse effects on humans by directly causing disease via low-dose exposure and indirect harm via antibiotic resistance. However, the current methods for antibiotic extraction and analysis in food have not yet formed a uniform standard, and only a few data exist regarding the residual antibiotic condition in various types of foods. Hence, we review the literature since 2008 to summarize analytical methods and residue status of antibiotics in food. Then, we discuss the causes of antibiotic residues in food and the possible hazards to human health. We hope that the joint efforts of the scientific community and political circles will lead to the formation of a unified standard for the extraction and analysis of antibiotics in food, to allow for comprehensive monitoring of residual antibiotics and ensure human health.

Carbon and Tin-Based Polyacrylonitrile Hybrid Architecture Solid Phase Microextraction Fiber for the Detection and Quantification of Antibiotic Compounds in Aqueous Environmental Systems

In this study, the detection and quantification of multiple classes of antibiotics in water matrices are proposed using a lab-made solid phase microextraction (SPME) fiber coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lab-made fiber was prepared using a graphene oxide (G), carbon nanotubes (C), and titanium dioxide (T) composite, namely GCT, with polyacrylonitrile (PAN) as supporting material. The detected antibiotics were enrofloxacin, sulfathiazole, erythromycin, and trimethoprim. The custom-made fiber was found to be superior compared with a commercial C18 fiber. The excellent reproducibility and lower intra-fiber relative standard deviations (RSDs 1.8% to 6.8%) and inter-fiber RSDs (4.5% to 8.8%) made it an ideal candidate for the detection of traces of antibiotics in real environmental samples. The proposed validated method provides a satisfactory limit of detection and good linear ranges with higher (>0.99) coefficient of determination in the aqueous system. Application of the method was made in different real water systems such as river, pond and tap water using the standard spiking method. Excellent sensitivity, reproducibility, lower amount of sample detection and higher recovery was found in a real water sample. Therefore, the extraction method was successfully applied to the detection and quantification of multiple classes of antibiotics in different aqueous systems with satisfactory results.

A Simple, Sensitive, and Reliable Method for the Simultaneous Determination of Multiple Antibiotics in Vegetables through SPE-HPLC-MS/MS

Antibiotics, widely used in livestock breeding, enter the environment through animal manure because of incomplete absorption in animals, especially the farmland ecosystem. Therefore, antibiotics may be adsorbed by plants and even become hazardous to human health through the food chain. In this study, a simple, sensitive, and reliable method was developed for the simultaneous determination of eleven antibiotics, including four sulfonamides, two tetracyclines, three fluoroquinolones, tylosin, and chloramphenicol in different vegetable samples using SPE-HPLC-MS/MS. Vegetable samples were extracted by acetonitrile added with hydrochloric acid (125:4, v/v). The extracts were enriched by circumrotating evaporation, and then cleaned through SPE on a hydrophilic-lipophilic balance (HLB) cartridge. All compounds were determined on a C₁₈ reverse phase column through HPLC-MS/MS. The mean recoveries of 11 antibiotics from spiked samples of vegetables ranged from 71.4% to 104.0%. The limits of detection and quantification were 0.06⁻1.88 μg/kg and 0.20⁻6.25 μg/kg, respectively. The applicability of this technique demonstrated its good selectivity, high efficiency, and convenience by the analysis of 35 vegetable samples available from a vegetable greenhouse. Antibiotic residues in vegetables have aroused wide concern from the public. Therefore, standards should be established for antibiotic residues in vegetables to ensure food safety and human health.