Multi-mycotoxin analysis in eggs using a QuEChERS-based extraction procedure and ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry

Emerging mycotoxin occurrence in chicken feed and eggs from Algeria

Poultry farming has developed into one of Algeria's most productive industrial farming because of the growing demand for sources of protein among Algerian society. Laying hen feed consists mainly of cereals, which can be contaminated with molds and subsequently with their secondary metabolites known as mycotoxins. These later can pose a serious danger to the production and quality of eggs in the commercial layer industry. This work focuses on the detection of emerging mycotoxins, mainly enniatins (ENNs) and beauvericin (BEA), in poultry feed and eggs from different locations in Algeria. Two different QuEChERS-based extractions were established to extract ENNs and BEA from chicken feed and eggs. The determination of mycotoxin occurrence was achieved by a UHPLC-MS/MS method using 0.1% (v/v) formic acid in water and MeOH as mobile phase, an ESI interface operating in positive mode, and a triple quadrupole mass spectrometer operating in MRM for the detection. Matrix-matched calibration curves were carried out for both matrices, obtaining good linearity (R2 > 0.99). The method performance was assessed in terms of extraction recovery (from 87 to 107%), matrix effect (from - 47 to - 86%), precision (RSD < 15%), and limits of quantitation (≤ 1.1 µg/kg for feed and ≤ 0.8 µg/kg for eggs). The analysis of 10 chicken feed samples and 35 egg samples composed of a 10-egg pool each showed that ENN B1 was the most common mycotoxin (i.e., found in 9 feed samples) with contamination levels ranging from 3.6 to 41.5 µg/kg, while BEA was detected only in one feed sample (12 µg/kg). However, eggs were not found to be contaminated with any mycotoxin at the detection limit levels. Our findings indicate that the searched mycotoxins are present in traces in feed and absent in eggs. This can be explained by the application of a mycotoxin binder. However, this does not put a stop on the conduction of additional research and ultimately setting regulations to prevent the occurrence of emerging mycotoxins.

Comprehensive profiling of amino acids and derivatives in biological samples: A robust UHPLC-MS/MS method for investigating acute lung injury

The severe respiratory dysfunctions associated with acute lung injury (ALI) and its sequelae have a high morbidity and mortality rate, are multifactorial, and lack a viable treatment. Considering the critical function that amino acids and derivatives play in the genesis of illnesses and the regulation of metabolic processes, monitoring the levels of metabolites associated with amino acids in biological matrices is necessary and interesting to study their pathological mechanisms. Exploring the dynamics of amino acids and derivatives level and searching for biomarkers provides improved clinical ideas for the diagnosis and treatment of ALI. Therefore, we developed an ultra-high-performance liquid chromatography-electrospray tandem mass spectrometry (UHPLC-MS/MS) method that can simultaneously determine the amino acid and derivatives metabolic levels to study amino acid profiles in different biological samples to facilitate clinical research of ALI. In this study, 48 amino acids and derivatives, including neurotransmitters, polyamines, purines, and other types, were quantified simultaneously in a fast, high-throughput, sensitive, and reliable manner within a 15-minute run time without derivatization. No relevant studies have been reported to quantify these 48 amino acid metabolites in three biological samples simultaneously. Satisfactory linearity (R > 0.995), inter-day and intra-day accuracy (85.17-112.67 % and 85.29-111.60 %, respectively), inter-day and intra-day precision (RSD < 13.80 % and RSD < 12.01 %, respectively), matrix effects (81.00 %-118.00 %), recovery (85.09 %-114.65 %) and stability (RSD < 14.72 %) were all demonstrated by the optimized method's successful validation for all analytes. In addition, the suggested method was effectively implemented in plasma, urine, and lung tissue from normal mice and mice with ALI, with the aim of finding potential biomarkers associated with ALI. Potential biomarkers were screened through multivariate statistical analysis and volcanic map analysis, and the changes of markers in ALI were again identified through heat map analysis and correlation analysis with biochemical indicators, which provided ideas and references for subsequent mechanism studies. Here, the technique created in this work offers a quick and dependable way to perform an integrated analysis of amino acids in a variety of biological materials, which can provide research ideas for understanding the physiopathological state of various diseases.

Detection and dietary risk of per- and polyfluoroalkyl substances in shellfish products from the coasts of Bohai Sea and South China Sea

Artificial per- and polyfluoroalkyl substances (PFASs) are widely distributed in the environment and are potentially harmful to human health. This study assessed the matrix effect of different shellfish on LC-MS analysis and the recoveries of PFASs in purified extracts purified by adding ENVI-Carb graphitized carbon black. Total 76 samples were collected from coastal cities of the Bohai Sea and South China Sea in China. Results showed that the signal response of perfluorocarboxylic acid increased with the length of fluorocarbon chains. ENVI-Carb can mitigate the shellfish matrix effects for analysis of PFASs. Ten PFASs components were detected in shellfish samples at concentrations ranging from 1.3 to 8.5 ng/g wet weight. The PFOA and PFHxS were the dominant components, and PFOA, PFTrDA and PFNA were detected at high rates of 58-93%. The highest levels of ∑PFASs were accumulated in clams, while the lowest levels were found in mussels. The dietary risk assessment indicated that PFASs potentially threaten human health via consumption of clam products in the Bohai Sea region. This study will improve the understanding of the contamination status and the dietary risk of PFASs in shellfish products along the coasts of Bohai Sea and South China Sea in China.

Multivariate surface self-assembly strategy to fabricate ionic covalent organic framework surface grafting monolithic sorbent for enrichment of aristolochic acids prior to high performance liquid chromatography analysis

Herein, an ionic covalent organic framework (iCOF) surface grafting monolithic sorbent was prepared by the multivariate surface self-assembly strategy for in-tube solid-phase microextraction (SPME) of trace aristolochic acids (AAs) in serum, traditional Chinese medicines (TCMs) and Chinese patent drug. Via adjusting the proportion of ionic COF building block during the self-assembly, the density of quaternary ammonium ions in the iCOF was modulated for the enhanced adsorption of AAs. The successful preparation of iCOF surface grafting monolithic sorbent was confirmed by different means. A multiple mode mechanism involving π-π stacking, hydrophobic, electrostatic and hydrogen-bonding interactions was primarily attributed to the adsorption. Several in-tube SPME operating conditions, such as the dosage of ionic COF building block, ACN percentage and TFA percentage in the sampling solution, ACN percentage and TFA percentage in eluent and the collection time span, were optimized to develop the online in-tube SPME-HPLC method for analysis of AAs. Under the optimized conditions, a good linearity was obtained in the concentration range of 20-1000 ng/mL for target AAs in serum samples, the limits of detection (LODs) were less than 10 ng/mL, while the recoveries ranged from 90.3 % to 98.7 % with RSDs (n = 5) below 7.9 %. This study developed a feasible approach to iCOF functionalized monolithic sorbent for SPME and further exhibited the vast potential for the application of COF based monolithic sorbent in sample preparation.

Synthesis of a core-shell magnetic covalent organic framework for the enrichment and detection of aflatoxin in food using HPLC-MS/MS

A porous magnetic covalent organic framework, Fe3O4@TPBD-TPA (terephthalaldehyde (TPA) , N, N, N', N'-tetrakis(p-aminophenyl)-p-phenylenediamine (TPBD)), was synthesized using the Schiff base reaction under mild reaction conditions. This adsorbent exhibited excellent adsorption performance for aflatoxins. The adsorption capacity of Fe3O4@TPBD-TPA for aflatoxins ranged from 64.4 to 84.4 mg/g. A magnetic solid-phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method based on Fe3O4@TPBD-TPA was developed for the efficient determination of four types of aflatoxins in food samples (maize, maize oil, peanut, and peanut oil). The determination coefficients (R2) were ≥0.9972. The method exhibited detection limits ranging from 0.01 to 0.06 μg/kg and spiked recoveries of 80.0 to 113.1%. The intra-day and inter-day precision were less than 6.77%, indicating good repeatability. The adsorbent showed promising prospects for the efficient enrichment of trace amounts of aflatoxins in complex food matrices.

Triblock copolymer–grafted restricted access materials with zwitterionic polymer outer layers for highly efficient extraction of fluoroquinolones and exclusion of proteins

High-selectivity and high-exclusion restricted access materials (RAMs) benefit the analysis of biological samples. Herein, triblock copolymer-functionalized poly(4-vinylbenzyl chloride-co-divinylbenzene) (P_VBC/DVB) microspheres were prepared via the sequential surface-initiated atom radical polymerization of hydrophobic styrene (St), ionic vinylimidazole (VIm), and zwitterionic sulfobetaine methacrylate (SBMA), affording RAMs with multiple interaction-adsorption sites and zwitterionic polymer exclusion sites on the internal and external surfaces of P_VBC/DVB. The preferential extraction of fluoroquinolones (FQs) is realized based on the hydrophobic/π-π/ion exchange interactions due to the grafted poly-St-VIm, and the zwitterionic poly-SBMA block in the triblock copolymers can efficiently exclude various proteins. A sensitive detection method for FQs in chicken was established by solid phase extraction with RAMs as adsorbent combined with UPLC-MS/MS, achieving wide linearity (2.0-200.0 ng mL^-1), low limit of detection (0.5 μg kg^-1) and limit of quantification (1.5 μg kg^-1), and good inter- and intraday precision with satisfactory recoveries (104.1%-117.7% and 115.3%-121.2% with RSDs < 12%).

Effect of Brassinolide on Soil Microorganisms in Millet Field Polluted by Tribenuron-Methyl

Tribenuron-methyl is used to control broad-leaved weeds and has a promising application prospect in millet fields. However, its negative impact on soil ecology cannot be ignored. Brassinosteroids have been widely reported to enhance plant resistance to stress, but information on brassinosteroids for the remediation of pesticide-contaminated soils is limited. Under field conditions, brassinosteroids were applied to explore their effects on the residues of tribenuron-methyl, soil enzyme activity, soil microbiol community, and millet yield. After applying brassinosteroids according to the dose of 150 mL hm^-2, the degradation rate of tribenuron-methyl accelerated. Brassinolide stimulated the activities of catalase and dehydrogenase, while the activities of sucrase and alkaline phosphatase were inhibited. The results of high-throughput sequencing showed that brassinosteroids inhibited the growth of Verrucomicrobia, Ascomycota, and Mortierellomycota and promoted the abundance of cyanobacteria. Additionally, brassinosteroids could also significantly increase the diversity index and change the community structure of soil bacteria and fungi. Further, the predicted function results indicated that brassinosteroids changed some metabolic-related ecological functions of the soil. We also found that brassinolide could increase millet yields by 2.4% and 13.6%. This study provides a theoretical basis for the safe use of tribenuron-methyl in millet fields and a new idea for the treatment of pesticide residues in soil.

Type B Trichothecenes in Cereal Grains and Their Products: Recent Advances on Occurrence, Toxicology, Analysis and Post-Harvest Decontamination Strategies

Type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol) and deoxynivalenol-3-glucoside (DON-3G) are secondary toxic metabolites produced mainly by mycotoxigenic Fusarium fungi and have been recognized as natural contaminants in cereals and cereal-based foods. The latest studies have proven the various negative effects of type B trichothecenes on human health. Due to the widespread occurrence of Fusarium species, contamination by these mycotoxins has become an important aspect for public health and agro-food systems worldwide. Hence, their monitoring and surveillance in various foods have received a significant deal of attention in recent years. In this review, an up-to-date overview of the occurrence profile of major type B trichothecenes and DON-3G in cereal grains and their toxicological implications are outlined. Furthermore, current trends in analytical methodologies for their determination are overviewed. This review also covers the factors affecting the production of these mycotoxins, as well as the management strategies currently employed to mitigate their contamination in foods. Information presented in this review provides good insight into the progress that has been achieved in the last years for monitoring type B trichothecenes and DON-3G, and also would help the researchers in their further investigations on metabolic pathway analysis and toxicological studies of these Fusarium mycotoxins.

Development of High-Throughput Sample Preparation Procedures for the Quantitative Determination of Aflatoxins in Biological Matrices of Chickens and Cattle Using UHPLC-MS/MS

Aflatoxins (AFs) frequently contaminate food and animal feeds, especially in (sub) tropical countries. If animals consume contaminated feeds, AFs (mainly aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and their major metabolites aflatoxin M1 (AFM1) and M2 (AFM2)) can be transferred to edible tissues and products, such as eggs, liver and muscle tissue and milk, which ultimately can reach the human food chain. Currently, the European Union has established a maximum level for AFM1 in milk (0.05 µg kg^-1). Dietary adsorbents, such as bentonite clay, have been used to reduce AFs exposure in animal husbandry and carry over to edible tissues and products. To investigate the efficacy of adding bentonite clay to animal diets in reducing the concentration of AFB1, AFB2, AFG1, AFG2, and the metabolites AFM1 and AFM2 in animal-derived foods (chicken muscle and liver, eggs, and cattle milk), chicken and cattle plasma and cattle ruminal fluid, a sensitive and selective ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed. High-throughput sample preparation procedures were optimized, allowing the analysis of 96 samples per analytical batch and consisted of a liquid extraction using 1% formic acid in acetonitrile, followed by a further clean-up using QuEChERS (muscle tissue), QuEChERS in combination with Oasis^® Ostro (liver tissue), Oasis^® Ostro (egg, plasma), and Oasis^® PRiME HLB (milk, ruminal fluid). The different procedures were validated in accordance with European guidelines. As a proof-of-concept, the final methods were used to successfully determine AFs concentrations in chicken and cattle samples collected during feeding trials for efficacy and safety evaluation of mycotoxin detoxifiers to protect against AFs as well as their carry-over to animal products.

Trace determination of fifteen free amino acids in drinking source water via solid-phase extraction coupled with liquid chromatography tandem mass spectrometry

Amino acids (AAs) are important nitrogen-containing organics in water, and a large number of reports have proven that they were the precursors of many nitrogen-containing disinfection by-products, some of which have cytotoxicity and carcinogenicity. However, little has been done on their occurrence in drinking source water. Therefore, a trace determination method via solid-phase extraction coupled with ultra-high pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for 15 free AAs (FAAs) was developed, which was successfully applied for drinking source water samples. For sample preparation, strong cation-exchange stationary solid-phase extraction (SPE) cartridge showed better extraction performance to that of reverse phase stationary oasis HLB SPE cartridge. The optimal water pH was determined to be 2.8 before extraction. Strong matrix effects for most FAAs were observed in this work; thus, sample extraction with SPE was recommended to eliminate the matrix effects. The developed method showed excellent linearity (R² > 0.991), low limits of detection (LODs, 0.01-0.27 nmol/L), and good recoveries of 69.8-117.9% in drinking source water with low relative standard deviations (RSDs, 0.3-13.2%). The developed method was finally applied to eight drinking source water samples, and the top five FAAs were found to be serine, glycine, leucine, alanine, and isoleucine.

Occurrence and Determination of Alternaria Mycotoxins Alternariol, Alternariol Monomethyl Ether, and Tentoxin in Wheat Grains by QuEChERS Method

The Alternaria mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tentoxin (TEN) are mycotoxins, which can contaminate cereal-based raw materials. Today, wheat is one of the most important crops in temperate zones, and it is in increasing demand in the Western Balkans countries that are urbanizing and industrializing. This research aimed to investigate the occurrence and determine the concentration of Alternaria mycotoxins AOH, AME, and TEN in wheat samples from the Republic of Serbia and the Republic of Albania, harvested in the year 2020 in the period between 15 June and 15 July. A total of 80 wheat grain samples, 40 from each country, were analyzed by an QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. From the obtained results, it can be seen that the mean concentration of AOH was 3.3 µg/kg and AME was 2.2 µg/kg in wheat samples from Serbia, while TEN from both Serbia and Albania was under the limit of quantification (<LOQ). The maximum of AOH and AME mycotoxins was recorded only in wheat grain samples collected in the Republic of Serbia (5.3 and 2.3 µg/kg). In conclusion, Alternaria mycotoxins have concentrations above the LOQ, which could be potentially considered a health hazard to both humans and animals.

Determination of multiple bisphenol analogues and their metabolites in human serum by liquid chromatography tandem mass spectrometry

To date, knowledge of internal human exposure to BPA and its analogues (particularly bisphenol S and bisphenol F, etc.) remains limited. In the present study, a method involving dispersive solid-phase extraction and LC/MS was proposed to investigate the contamination levels of 28 precursor bisphenols and 9 major metabolites in serum. The critical variables of preparation method were screened out by Plackett-Burman design and further optimized by central composite design. Left in optimal conditions, a total of 286 samples consisting of 153 males and 133 females were analyzed. The results showed that BPA dominated over all the cases with the highest positive rate (82.2% of all the surveyed people), and totally four metabolites (BPA β-D-glucuronide, BPA monosulfate, BPA bis-(β-D-glucuronide) and BPS monosulfate) were detectable. The occurrence of BPA bis-(β-D-glucuronide) in serum is reported for the first time and its higher positive rate and contamination concentrations suggested that it may be a more important metabolite of BPA than others. Negligible potential risk of health effects to blood donors was observed, since the estimated exposure levels (mean 32.1 ng/kg bw/day, 95th 123.2 ng/kg bw/day) were well below far less than the temporary tolerable reference dose of BPA that recommended by the European Food Safety Authority (4 μg/kg bw/day by). The reference level of BPA for healthy population was determined to be 4.09 μg/L via the percentile method.

Prevalence of Aflatoxin Contamination in Peanuts and Peanut Butter from an Informal Market, Harare, Zimbabwe

Peanuts and peanut butter play an important role nutritionally in improving the diets of individuals in many parts of Africa, especially in the fight against child malnutrition. However, in developing countries such as Zimbabwe, most of the raw peanuts and peanut butter produced in backyard industries are sold in informal markets and rarely undergo formal safety inspection for aflatoxin contamination. The objective of the study was to determine the prevalence of aflatoxins in raw peanuts and backyard peanut butter sold at Mbare informal market. Ten (10) raw peanut samples and twenty (20) peanut butter samples were collected from Mbare informal market. Aflatoxin contamination was determined using liquid chromatography-mass spectrometry (LC-MS). The results revealed that sixty percent (60%) of the raw peanut samples were contaminated with total aflatoxin ranging from <0.75 to 426.4 μg/kg. One hundred percent (100%) of peanut butter samples were contaminated with total aflatoxins ranging from 4.7 μg/kg to 435.0 μg/kg. Aflatoxin B₁ was the most prevalent aflatoxin in both raw peanuts (range, 1.2 μg/kg to 90.8 μg/kg) and peanut butter (range, 4.7 to 382.9 μg/kg). Forty percent (40%) of the raw peanuts and 95% of peanut butter samples exceeded the maximum limits of AFB₁ as set by Zimbabwe legislation. The results suggest that raw peanuts and especially the peanut butter from backyard industries are heavily contaminated with aflatoxins and could constitute a possible health risk to consumers who regularly purchase these food commodities from informal markets.

Water based-deep eutectic solvent for ultrasound-assisted liquid-liquid microextraction of parabens in edible oil

A novel water-based deep eutectic solvent was synthesized and used for the ultrasound-assisted liquid-liquid microextraction of parabens in edible oil and for their determination by high performance liquid chromatography. Herein, the water-based deep eutectic solvent was formulated at room temperature by tetrabutylammonium chloride as hydrogen bond acceptor and water as hydrogen bond donor at the molar ratio of 1:5. As component, water has the effect on tailoring the physicochemical properties of water-based deep eutectic solvent and assisting tetrabutylammonium chloride (hydrogen bond acceptor) capturing parabens (hydrogen bond donor) through in-situ deep eutectic solvent formation. The developed method has satisfactory linearity (1.5-500 μg/L), limits of detections (0.2-0.4 μg/L), precisions (RSDs ≤ 5.8%), and was fruitfully applied to detect parabens in edible oil with excellent recoveries (85.1-106.8%). The feature of the procedure lies in simplicity, low cost and high sensitivity, and this can be extended for the efficient separation of other hydrophobic compounds.

Ochratoxin A potentiates citrinin accumulation in kidney and liver of rats

Ochratoxin A (OTA) and citrinin (CTN) are nephrotoxic mycotoxins often found together in grain. The aim of this study was to measure their accumulation in the kidney and liver of adult male Wistar rats, see how it would be affected by combined treatment, and to determine if resveratrol (RSV) would decrease their levels in these organs. The rats received 125 or 250 mg/kg bw of OTA by gavage every day for 21 days and/or 20 mg/kg bw of CTN a day for two days. Two groups of rats treated with OTA+CTN were also receiving 20 mg/kg bw of RSV a day for 21 days. In animals receiving OTA alone, its accumulation in both organs was dose-dependent. OTA+CTN treatment resulted in lower OTA but higher CTN accumulation in both organs at both OTA doses. RSV treatment increased OTA levels in the kidney and liver and decreased CTN levels in the kidney. Our findings point to the competition between CTN and OTA for organic anion transporters 1 and 3.

QuEChERS sample pre-processing with UPLC-MS/MS: A method for detecting 19 quinolone-based veterinary drugs in goat's milk

We develop and validate a method for the rapid determination and identification of 19 quinolones in goat's milk by combining the QuEChERS technique with ultra-performance liquid chromatography-tandem mass spectrometry. Plackett-Burman and Central Composite Design methods were used to select the parameters that best promote the extraction efficiency, which led to extraction with acetonitrile/5% formic acid, followed by phase separation with sodium citrate, disodium hydrogen citrate, Na₂SO₄, and NaCl as optimal. The supernatant was then extracted and cleaned by dispersive solid-phase extraction using C₁₈ and Na₂SO₄ aided by low-temperature clean-up. The method was validated, with limits of quantification (LOQs) of 5 ppb, specificities of 1/5 LOQ, linearities (R²) > 0.9853, recoveries of 73.4-114.2%, repeatabilities < 15.0%, and intermediate precisions < 13.6%. The developed method was suitable for the routine analysis of quinolone residues in goat's milk and was used to test 10 goat milk samples produced in Taiwan.

Hydrophilic-interaction-based magnetically assisted matrix solid-phase dispersion extraction of carbadox and olaquindox in feeds

BACKGROUND

Carbadox and olaquindox have been banned from feeds since 1998 by the EU because of their mutagenic, photoallergic, and carcinogenic effects. Unfortunately, owing to their outstanding effect, they are frequently abused or misused in animal husbandry. There is an urgent need to develop a sensitive and reliable method for monitoring these drugs in animal feeds.

RESULTS

This work reported a new method of hydrophilic-interaction-based magnetically assisted matrix solid-phase dispersion (MMSPD) extraction coupled with reversed-phase liquid chromatography-mass spectrometry for simultaneous determination of carbadox and olaquindox in animal feeds. 3-Trimethoxysilylpropyl methacrylate (γ-MAPS)-modified attapulgite (ATP) was crosslinked with γ-MAPS-modified iron(II,III) oxide (Fe₃ O₄ ), 1-vinyl-3-(butyl-4-sulfonate) imidazolium (VBSIm), acrylamide (AM), and N,N'-methylene-bis(acrylamide) (MBA) to synthesize ATP@Fe₃ O₄ @poly(VBSIm-AM-MBA) particles. The resultant particles were characterized by scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, vibrating sample magnetometer, and Fourier transform infrared spectroscopy. Crosslinking of ATP into the magnetic particles has significantly increased the adsorption capacity of the particles. Under optimum conditions, the limits of detection (S/N = 3) were 0.3 μg kg^-1 and 0.9 μg kg^-1 for carbadox and olaquindox respectively. The intra-day and inter-day recoveries of the spiked targets in feed samples were in the range 83.5-98.3% with relative standard deviations of 1.0-8.3%.

CONCLUSION

With a simplified procedure and a low amount of sample, the proposed hydrophilic-interaction-based MMSPD method is not only useful for the determination of carbadox and olaquindox in feeds but also holds great promise for the analysis of other polar targets in solid or semisolid matrices. © 2021 Society of Chemical Industry.

Research and Application of In Situ Sample-Processing Methods for Rapid Simultaneous Detection of Pyrethroid Pesticides in Vegetables

A novel rapid and cost-effective pre-processing method for the simultaneous determination of pyrethroid pesticides in vegetables has been developed and validated. The process of pesticide extraction was carried out by the QuEChERS (quick, easy, cheap, effective, rugged and safe) method combined with filtration by filter paper, and cleanup was carried out by the multi-plug-filtration-cleanup (m-PFC) method with no centrifuge program during the whole process. The pre-processing method is optimized for gas chromatography (GC). The process is convenient and time saving, requiring just a few seconds per sample. The recovery rate (70–120%), limit of detection (0.0001–0.007 mg/kg), precision (0.2–9.3%) and accuracy for each analyte were determined in 10 representative vegetables with good results. Finally, the feasibility of the developed method was further confirmed by the successful determination of pyrethroid-pesticide residues in pyrethroid-containing practical samples within the processing method coupled with thin-layer chromatography and a colloidal-gold test strip.

Screening of multi-mycotoxins in fruits by ultra-performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry

A modified quick, easy, cheap, effective, rugged, and safe extraction procedure combined with ultra-performance liquid chromatographic separation and ion mobility quadrupole time-of-flight mass spectrometry was developed to determine the presence of 20 mycotoxins (i.e., Alternaria toxins, ochratoxin, patulin, aflatoxin and trichothecenes) in fruit samples from Xinjiang. A complete platform, including screening via an in-house library, confirmation and quantification using reference standards, was established, which provided accurate MS data and complete spectra containing the fragment ions for each analyte. To evaluate the performance of the developed method, satisfactory validation parameters, such as linearity (R² ≥ 0.9992), precision (RSDs ≤ 9.8%), recovery (81.2-99.2%), LOD (0.06-2.22 µg kg^-1), and LOQ (0.2-7.39 µg kg^-1), were obtained. The analysis of 130 fruit samples revealed nonnegligible contamination with mycotoxins; specifically, the highest levels of three Alternaria toxins were detected in jujube, wolfberries and raisins.

Investigation on the occurrence and contamination of multi-mycotoxin in chestnut and jujube (red date)

A rapid and efficient QuEChERS-based preparation method was established for the simultaneous determination of 43 mycotoxins in chestnut and jujube (Chinese date). The contaminants were extracted using acetonitrile and subjected to dispersive solid-phase extraction for further clean-up. Central composite design was conducted to overcome the limitations of conventional optimization methods, and assess the interaction effects between variables and reach the true optimal conditions. Quantitative analysis was performed on UHPLC-MS/MS with the aid of stable isotope internal standards and matrix-matched curves, whereas qualitative identification was carried out by using high-resolution MS based on exact masses and fragmentation patterns. In addition to the mycotoxins that are routinely monitored (like aflatoxins, ochratoxin A, etc.), this study also revealed a non-negligible contamination of zearalenone (56/170), beauvericin (52/170), enniatin B (43/170), and alternariol monomethyl ether (42/170) in chestnut and jujube, especially the chestnut flour.

Performance of different extraction methods for paralytic shellfish toxins and toxin stability in shellfish during storage

Accurate analysis of paralytic shellfish toxins (PSTs) in shellfish is important to protect seafood safety and human health. In this study, the performance of different extraction protocols for PSTs from scallop tissues is compared and discussed, including regular extraction solvents hydrochloric acid (HCl) and acetic acid (AcOH) followed by heating and solid-phase extraction (SPE) purification, and a novel technique of matrix solid-phase dispersion (MSPD) without heating. The possible conversion of C1/2 and GTX2/3 standards after heating, and the stability of PSTs in wet scallop tissues stored at -20 °C for a 6-month period are also explored. Results showed that the MSPD technique could effectively mitigate matrix interference, but its recoveries of PSTs were significantly lower than those of the HCl and AcOH extraction methods followed by carbon SPE purification. The molar concentrations of M-toxins obtained by the MSPD method were generally lower than those analyzed by the HCl and AcOH extraction methods, which demonstrated a weak chemical conversion of C1/2 and GTX2/3 due to the heating process. Most of the PSTs were relatively stable in scallop tissues during 1-month storage at -20 °C, while the concentrations of PSTs in scallop tissues obviously changed after 6 months due to the degradation and transformation of PSTs during long-term storage at -20 °C. This work helps improve our understanding of the performance of different extraction methods and the stability of PSTs in scallop tissues stored at -20 °C.

A global systematic review and meta-analysis of concentration and prevalence of mycotoxins in birds' egg

In the current study, the concentration and prevalence of birds' egg's mycotoxins among 11 articles (66 studies) based on countries, part of eggs, and type of mycotoxins subgroups were meta-analyses using a random-effect model. The order of mycotoxin according to concentration of mycotoxin was Deoxynivalenol (20.083 μg/kg) > Zearalenone (2.065 μg/kg) > Enniatin (1.120 μg/kg) > Total aflatoxin (0.371 μg/kg) > Beauvericin (0.223 μg/kg) > Ochratoxins (0.087 μg/kg) > Citrinin (0.010 μg/kg). Further, the mycotoxins' concentration in the yolk part (2.070 μg/kg) was higher than the mixed eggs (0.283 μg/kg). The rank order of mycotoxin based on country was China (14.990 μg/kg) > Cameroon (7.594 μg/kg) > Thailand (1.870 μg/kg) > Finland (0.920 μg/kg) > Iran (0.312 μg/kg) > Jordan (0.202 μg/kg) > Belgium (0.183 μg/kg) > Spain ( South Korea ( DON (85.00%) > AFT (20.15%) > OT (16.00%). The overall prevalence of mycotoxin was equal to 29.65%. Also, the concentration of mycotoxins in China and Cameroon was higher than in other countries. Therefore, the monitoring programs to reduce mycotoxins in bird eggs consumed in some countries such as China and Cameroon should be considered.

Optimization of the QuEChERS-Based Analytical Method for Investigation of 11 Mycotoxin Residues in Feed Ingredients and Compound Feeds

Mycotoxins are toxic substances naturally produced by various fungi, and these compounds not only inflict economic damage, but also pose risks to human and animal health. The goal of the present study was to optimize the QuEChERS-based extraction and liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the analysis of 11 mycotoxins, such as aflatoxins (AFs), ochratoxin A (OTA), fumonisins (FBs), T-2 toxin, HT-2 toxin, zearalenone (ZEN), and deoxynivalenol (DON), commonly found in feed. The QuEChERS method, characterized by being “quick, easy, cheap, effective, rugged, and safe”, has become one of the most common extractions and clean-up procedures for mycotoxin analyses in food. Therefore, in this experiment, an optimal method for the analysis of 11 mycotoxins in feed was established by modifying the general QuEChERS method. In this process, it was confirmed that even if feed samples of different weights were extracted, the quantitative value of mycotoxins in the feed was not affected. To reduce matrix effects, 13C-labeled compounds and deuterium were used as internal standards. This optimized method was then applied in the determination of 11 mycotoxins in 736 feed ingredients and compound feeds obtained from South Korea. The results showed that the occurrence rates of FBs, ZEN, and DON were 59.4%, 38.0%, and 32.1%, respectively, and OTA, AFs, and T-2 toxin and HT-2 toxin were found in fewer than 1% of the 736 feeds. The mean concentration ranges of FBs, ZEN, and DON were 757–2387, 44–4552, and 248–9680 μg/kg, respectively. Among the samples in which DON and ZEN were detected, 10 and 12 samples exceeded the management recommendation standards presented by the Ministry of Agriculture, Food and Rural Affairs (MAFRA). However, when the detected concentrations of DON and ZEN were compared with guideline levels in foreign countries, such as the US, Japan, China, and the EU, the number of positive samples changed. In addition, the co-occurrence of mycotoxins in the feed was analyzed, and the results showed that 43.8% of the samples were contaminated with two or three mycotoxins, among which the co-occurrence rate of FBs, ZEN, and DON was the highest. In conclusion, these results suggest the need for stricter management standards for FBs, DON, and ZEN in South Korea, and emphasize the importance of the continuous monitoring of feeds.

A reciprocating magnetic field assisted on-line solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry determination of trace tetracyclines in water

A reciprocating magnetic-field-assisted on-line solid-phase extraction (RMF-SPE) method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for continuous enrichment of trace chemicals in water samples. Under the assist of the reciprocating magnetic field, carboxyl-modified magnetic nanoparticles (CMNPs) were applied to prepare microcolumn with even dispersion by periodical motion, instead of traditional compaction as extraction sorbents. When water sample passed through the extraction region, dynamic sorbents generates an advantage of countless contacts between sorbents and targets without blocking for high efficient extraction. In this study, the on-line RMF-SPE method was established and evaluated by determination of tetracyclines (TCs) from water samples as analysis models, including oxytetracycline, tetracycline, demeclocycline, metacycline, chlortetracycline, and doxycycline. Experimental conditions have been investigated such as flow rate, reciprocating speed, elution time, and so on. The method showed high relative recovery (95.4-111.1%) and good repeatability with RSD from 2.9 to 11.8% for the 200 mL water sample. The linearity range, limits of detection (LODs), and limits of quantification (LOQs) were 0.5-200 μg L^-1 (chlortetracycline) and 0.1-200 μg L^-1 (other TCs), 12.0-74.1 ng L^-1, and 40.1-247 ng L^-1, respectively. More importantly, the high enrichment factors in a range of 204 (chlortetracycline) to 276 (demeclocycline) indicate that a small amount of dynamic sorbents (only 10 mg) give full play to extraction attributing to the reciprocating movement, especially for trace analysis and continuous extraction, which is significant for water samples from sea, river and domestic waste.

A Novel Multiplex Mycotoxin Surface-Enhanced Raman Spectroscopy Immunoassay Using Functional Gold Nanotags on a Silica Photonic Crystal Microsphere Biochip

A novel multiplex mycotoxin surface-enhanced Raman spectroscopy (SERS) immunoassay was established for the first time on different artificial antigen-modified silica photonic crystal microspheres (SPCMs), which can be integrated into a biochip array to achieve multiplex detection using corresponding antibody-functionalized gold nanoparticles (AuNPs) as the SERS nanotag. The unique optical structure of SPCMs is helpful to find the detection spots easily, accommodate a large amount of probe molecules, and enhance the Raman signal intensity. Such enhancement was confirmed by the simulation result, showing the electric field enhancing effect in SPCMs with AuNPs being 7 times. A competitive SERS immunoassay was established using antigen-modified SPCMs and mycotoxins to compete for binding antibody-functionalized SERS nanotags, displaying broad linear detection ranges of 0.001-0.1 ng/mL for aflatoxin B₁ (AFB₁), 0.01-10 ng/mL for ochratoxin A (OTA), and 0.001-0.1 ng/mL for zearalenone (ZEN) and low detection limits of 0.82 pg/mL for AFB₁, 1.43 pg/mL for OTA, and 1.00 pg/mL for ZEN. In the spiked cereal samples, recovery rates of the method were measured in the range of 70.35-118.04% for the three mycotoxins, which was in agreement with that of the traditional enzyme-linked immunosorbent assay method. The SERS immunoassay for mycotoxin detection also showed high specificity and good repeatability and reproducibility. The new microsphere-based SERS immunoassay biochip only requires a one-step reaction and overcomes the disadvantages of fluorescence and chemiluminescence background signals. The work paves the way for further developing SERS-based microsphere suspension arrays for new targets.

Multi-residue method for the detection of 40 β-lactam-antibiotics in vaccines by LC-MS/MS

Antibiotics are widely used to treat bacterial infections during the process of vaccine production and storage resulting in antibiotic residues that can cause serious harm. A simple and sensitive method for residue analysis of 40 β-lactam antibiotics was developed and validated for vaccines including inactivated enterovirus 71 vaccine (Vero cells), recombinant hepatitis B vaccine (Saccharomyces cerevisiae), and live attenuated varicella vaccine using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI- MS/MS). Samples were prepared with acetonitrile as the protein precipitant. LC separation was performed on a C₁₈ column. These analytes were determined by LC-MS/MS operating multiple-reaction monitoring (MRM) scans in positive mode. The ranges for limits of detection (LOD) and quantification (LOQ) were as follows: 0.02-4 ng/dose (S/N ≥ 3) and 0.04-10 ng/dose in inactivated enterovirus 71 vaccine (Vero cells) and recombinant hepatitis B vaccine (Saccharomyces cerevisiae), 0.04-16 ng/dose and 0.2-20 ng/dose in live attenuated varicella vaccine. The ranges of recoveries of all antibiotics were 84.5%-108.2% in inactivated enterovirus 71 vaccine (Vero cells), 73%-108% in recombinant hepatitis B vaccine (Saccharomyces cerevisiae), and mostly 68.2%-107.8% in live attenuated varicella vaccine. This method simultaneously offers qualitative and quantitative analysis of multi-antibiotics in vaccines, which improves vaccine safety.

Efficacy of a Modified Clinoptilolite Based Adsorbent in Reducing Detrimental Effects of Ochratoxin A in Laying Hens

Background: The objective of this study was to evaluate the efficacy of modified clinoptilolite (Minazel Plus^®, MZ) as a mycotoxin adsorbent for preventing the negative the effects of ochratoxin A (OTA) on performance, pathohistological changes, and OTA residue in the eggs of laying hens. Methods: Forty eight (n = 48) laying hens (27 weeks old) were equally divided into six groups and depending on the type of addition were allocated to the following experimental treatments for 7 weeks: E-I group-1 mg/kg OTA; E-II group 0.25 mg/kg OTA; E-III group 1 mg/kg OTA + 0.2% of MZ; E-IV group 0.25 mg/kg OTA + 0.2% of MZ; MZ group supplemented with 0.2% of the adsorbent; and control (K, without feed additive). Results: Overall, the addition of 0.2% MZ to laying hen feed mitigated the harmful effects of OTA on target organs and reduced the presence of OTA residue in eggs. The groups that received 0.2% of MZ achieved better production results in terms of body weight, number of eggs, and feed consumption, compared to the other treatments. Conclusions: The current findings confirm the efficacy of MZ in preventing performance losses in laying hens exposed to OTA, as well as for improving the welfare and health of food producing animals.

The Existing Methods and Novel Approaches in Mycotoxins' Detection

Mycotoxins represent a wide range of secondary, naturally occurring and practically unavoidable fungal metabolites. They contaminate various agricultural commodities like cereals, maize, peanuts, fruits, and feed at any stage in pre- or post-harvest conditions. Consumption of mycotoxin-contaminated food and feed can cause acute or chronic toxicity in human and animals. The risk that is posed to public health have prompted the need to develop methods of analysis and detection of mycotoxins in food products. Mycotoxins wide range of structural diversity, high chemical stability, and low concentrations in tested samples require robust, effective, and comprehensible detection methods. This review summarizes current methods, such as chromatographic and immunochemical techniques, as well as novel, alternative approaches like biosensors, electronic noses, or molecularly imprinted polymers that have been successfully applied in detection and identification of various mycotoxins in food commodities. In order to highlight the significance of sampling and sample treatment in the analytical process, these steps have been comprehensively described.

Polyethyleneimine-functionalized Fe3O4/attapulgite particles for hydrophilic interaction-based magnetic dispersive solid-phase extraction of fluoroquinolones in chicken muscle

Fluoroquinolone (FQ) residues in foods of animal origin may threaten public health but are challenging to determine because of their low contents and complex matrices. In this study, novel polyethyleneimine-functionalized Fe₃O₄/attapulgite magnetic particles were prepared by a simple co-mixing method and applied as hydrophilic sorbents for the magnetic dispersive solid-phase extraction (MSPE) of three FQs, i.e., ciprofloxacin, norfloxacin, and enrofloxacin, from chicken muscle samples. The preparation of the magnetic particles was of high reproducibility and the products could be reused many times with high adsorption capacity. The key experimental factors possibly influencing the extraction efficiencies, including sample solution, extraction time, sample loading volume, desorption solution, desorption time, and elution volume were investigated. Under optimum MSPE conditions, the analytes in chicken muscle samples were extracted and then determined by RPLC-MS/MS in MRM mode. Good linearity was obtained for the analytes with correlation coefficients ranged from 0.9975 to 0.9995. The limits of detection were in the range of 0.02-0.08 μg kg^-1, and the recoveries of the spiked FQs in chicken muscle samples ranged from 83.9 to 98.7% with relative standard deviations of 1.3-6.8% (n = 3). Compared with the traditional MSPE methods based on hydrophobic mechanism, this hydrophilic interaction-based method significantly simplifies the sample pretreatment procedure and improves repeatability. This method is promising for accurate monitoring of FQs in foods of animal origin.

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.

Determination of estrogens and estrogen mimics by solid-phase extraction with liquid chromatography-tandem mass spectrometry

An analytical method has been developed and validated for the determination of six estrogens and estrogen mimics, namely estriol (E3), bisphenol A (BPA), 17β-estradiol (E2), estrone (E1), ethynyl estradiol (EE2) and dienestrol (DIE), with frequent occurrence in the natural environment. Solid phase extraction coupled with liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) using electrospray ionization (ESI) in a negative mode was applied to concentration, identification, and quantification of estrogens and estrogen mimics. The SPE conditions were optimized as the selection of C18 as cartridges and MeOH as an eluent, and the control of solution pH at 9.0. The method was validated by satisfactory recoveries (80-130%) and intra-day and inter-day precision (<18.4%, as relative standard deviation), and excellent linearity for calibration curves (R² > 0.996). The limits of detection (LODs) for six target estrogenic compounds ranged between 2.5 and 19.2 ng/L. The effects of matrix background on the determination were evaluated in terms of LODs, LOQs, analyte recovery, and slopes of calibration curves in five different water matrices. Matrix effects by tap water were negligible. However, both matrix suppression and enhancement (i.e., E3, E1, DIE) were observed in surface water and wastewater. The positive correlation between LODs and TOC in various water matrices indicated the negative effect of organic pollutants on the method sensitivity. The sum of target estrogenic compounds in environmental samples were within 17-9462 ng/L.

Determination of Toxic Pyrrolizidine Alkaloids in Traditional Chinese Herbal Medicines by UPLC-MS/MS and Accompanying Risk Assessment for Human Health

Pyrrolizidine alkaloids (PAs) are a class of natural toxins with hepatotoxicity, genotoxicity and carcinogenicity. They are endogenous and adulterated toxic components widely found in food and herbal products. In this study, a sensitive and efficient ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was used to detect the PAs in 386 kinds of Chinese herbal medicines recorded in the Chinese Pharmacopoeia (2020). The estimated daily intake (EDI) of 0.007 μg/kg body weight (bw)/day was adopted as the safety baseline. The margin of exposure (MOE) approach was applied to evaluate the chronic exposure risk for the genotoxic and carcinogenic potential of PAs. Results showed that PAs was detected in 271 out of 386 samples with a content of 0.1–25,567.4 μg/kg, and there were 20 samples with EDI values above the baseline, 0.007 μg/kg bw/day. Beyond that, the MOE values for 10 out of 271 positive samples were below 10,000. Considering the actual situation, Haber’s rule was used to assume two weeks exposure every year during lifetime, and still the MOE values for four out of 271 positive samples were under 10,000, indicating these products may have potential health risk. The developed method was successfully applied to detect the PAs-containing Chinese herbal medicines. This study provides convincing data that can support risk management actions in China and a meaningful reference for the rational and safe use of Chinese herbal medicines.

Novel synthesized attapulgite nanoparticles-based hydrophobic monolithic column for in-tube solid-phase microextraction of thiosildenafil, pseudovardenafil, and norneosildenafil in functional foods

In this study, a novel method which involved in-tube solid-phase microextraction (SPME) using an attapulgite (ATP) nanoparticles-based hydrophobic monolithic column was successfully developed. It was coupled with high-performance liquid chromatography-ultraviolet detection for the determination of three phosphodiesterase-5 (PDE-5) inhibitors, including thiosildenafil, pseudovardenafil, and norneosildenafil, in functional foods. The monolithic column was prepared by one-step polymerization, using 3-trimethoxysilylpropyl methacrylate-modified ATP nanoparticles and 1-butyl-3-vinylimidazolium bromide (VBIMBr) as the functional monomers, and ethylene glycol dimethacrylate (EDMA) as the cross-linker. The obtained poly(ATP-VBIMBr-EDMA) monolith was characterized by scanning electron microscopy equipped with energy-dispersive analysis of X-ray, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. The adsorption capacity, up to 2.00 μg/cm calculated by the Langmuir isotherm model, was about six times that of the poly(VBIMBr-EDMA) monolith. Crucial factors affecting the extraction efficiency, including sample solvent, elution solvent, flow rates of sampling loading and elution, sample loading volume, and elution volume, were investigated in details. Under the optimal in-tube SPME conditions, the proposed method showed good reproducibility with run-to-run, column-to-column, and batch-to-batch relative standard deviations less than 7.2%, and low limits of detection of 0.5-0.9 ng/mL in real samples. Thiosildenafil was detected in four types of functional foods with the contents of 1.30-4.78 μg/g. This newly proposed in-tube SPME method based on poly(ATP-VBIMBr-EDMA) monolith may provide a simple, efficient, and promising alternative to daily monitoring of PDE-5 inhibitors in functional foods.

Evaluation of different strategies to minimize the matrix effects on LC-MS/MS analysis of multiple lipophilic shellfish toxins in both acidic and alkaline chromatographic conditions

Lipophilic shellfish toxins (LSTs) accumulated by shellfish pose a potential threat to consumer health. A mandatory routine monitoring of LSTs has been adopted for seafood products by liquid chromatography-mass spectrometry (LC-MS) in many countries. In this study, two methods developed on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) under acidic and alkaline chromatographic conditions were assessed for the determination of multiple LSTs. Different strategies including matrix solid-phase dispersion (MSPD), solid phase extraction (SPE) and sample dilution were applied and evaluated the matrix effects of mussel, scallop, clam, and oyster samples on the signal response of mass spectrometry. Results showed that the alkaline method achieved a lower limit of detection (LOD) and more robust compared to the acidic method. The obvious signal suppression of OA and DTX1 (55%-76%) and signal enhancement of PTX2 (27%-34%) occurred in the crude extracts of shellfish under acidic chromatography. In the alkaline method, no remarkable matrix effects of crude extracts were found except for the scallop matrix on the signal intensity of DTX1, AZA3 and GYM-A (121%-130%). Clean-up methods MSPD, SPE and sample dilution obviously reduced the inhibition of shellfish matrices on the signal response of OA and DTX1, however, which were still subject to signal inhibition under acidic condition. Sample dilution was more effective than SPE and MSPD in minimizing the matrix interference in both acidic and alkaline methods. Furthermore, sample dilution in combination with the alkaline chromatography was the most effective method. Bivalve mollusks harvested from Beibu Bay, South China Sea, were generally contaminated by GYM-A and SPX1 at low concentrations.

Screening of multiclass pesticide residues in maca and Moringa oleifera by a modified QuEChERS sample preparation procedure and UPLC-ESI-MS/MS analysis

In the present study, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was proposed for the simultaneous analysis of 75 pesticides in maca and Moringa oleifera with ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). The developed method was validated in accordance with linearity, linear range, limit of detection, limit of quantification, accuracy, precision, and matrix effect. Each analyte had good linearity (R² > 0.99) in the corresponding concentration range. The method LOD and LOQ values of all the analytes ranged from 0.01 μg kg⁻¹ to 303.35 μg kg⁻¹ and 0.03 μg kg⁻¹ to 1011.15 μg kg⁻¹, respectively. The recoveries (n = 6) of the analyzed pesticides were in the range of 75.92–113.43%. The RSDs of precision were between 0.60% and 7.36%. All matrix effect values ranged from 81.79% to 118.71% and 80.36% to 119.64% in maca and Moringa oleifera, respectively. The analysis of 103 samples showed the presence of isofenphos-methyl in some of them. The method had a good application prospect and could be used as a general approach for the quantitative determination of pesticide residues in food.

In the present study, a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was proposed for the simultaneous analysis of 75 pesticides in maca and Moringa oleifera with UPLC-ESI-MS/MS.

Recent Progress and Development of G-Quadruplex-Based Luminescent Assays for Ochratoxin A Detection

Ochratoxin A (OTA) is a mycotoxin that is widespread throughout the world. It contaminates foods such as vegetables, fruits, and rice. It harms human health and has potential carcinogenic effects. The G-quadruplex (G4) is a tetraplexed DNA structure generated from guanine-rich DNA that has found emerging use in aptamer-based sensing systems. This review outlines the status of OTA contamination and conventional detection methods for OTA. Various G4-based methods to detect OTA developed in recent years are summarized along with their advantages and disadvantages compared to existing approaches.

Modified EMR-lipid method combined with HPLC-MS/MS to determine folates in egg yolks from laying hens supplemented with different amounts of folic acid

Egg yolks are a good source of folates. However, the method for analyzing the naturally occurring folates in egg yolks is complicated and time-consuming. In this study, a simplified pre-treatment method followed by validated HPLC-MS/MS was developed to determine native folates in eggs from laying hens treated with different amounts of folic acid. The modified enhanced matrix removal -lipid method to purify samples showed good performance in lipid elimination, reduction of steps and time savings. According to experimental analysis, yolks contained total folate amounts ranging from 147 to 760 μg/100 g when laying hens' diet was supplemented with folic acid from 0 to 10 mg/kg. Four folate vitamers were detected in egg yolks: 5-methyltetrahydrofolate accounted for 91-98% of total folates, whereas folic acid, 5-formyltetrahydrofolate and 10-formylfolic acid together accounted for 2-9%. Therefore, laying hens efficiently converted folic acid in feed into 5-methyltetrahydrofolate in eggs with little folic acid deposition.

Molecularly imprinted polymer solid phase extraction coupled with liquid chromatography-high resolution mass spectrometry for the detection of gonyautoxins 2&3 in seawater

Paralytic shellfish toxins (PSTs) cause risks to human health through food chains. Understanding the change of PSTs in seawater is critical for predicting the safety of seafood. Most reported methods for the detection of PSTs in microalgae or shellfish are not applicable in seawater because of extremely low concentration and matrix interferences. High resolution mass spectrometry (HRMS), quadrupole exactive orbitrap detects molecular ions accurately, and molecularly imprinted solid-phase extraction (MISPE) is recognized effective to reduce the matrix interference. GTXs 2&3 are two of common marine toxins in PSTs. In this study, a sensitive method consisting MISPE and liquid chromatography LC-HRMS was developed for the detection of GTXs 2&3 with a limit of detection (LOD) of 47.4 ng/L in seawater. With this method, samples obtained from the estuaries of the Shuangtaizi and Daliao Rivers were analyzed, and the results indicated the concentrations were lower than LOD in the area under investigation.