Quick, Easy, Cheap, Effective, Rugged, Safe Research Articles

Development of a Modified QuEChERS Method Based on Magnetic Multi-Walled Carbon Nanotubes as a Clean-Up Adsorbent for the Analysis of Heterocyclic Aromatic Amines in Braised Sauce Beef.

Heterocyclic aromatic amines (HAAs) generated during the cooking of meats cause adverse effects on human health. The purpose of the current research was to develop a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method using magnetic multi-walled carbon nanotubes (Fe3O4-MWCNTs) as clean-up adsorbents for the rapid determination of HAAs in braised sauce beef. The significant parameters in extraction and clean-up processes were screened and optimized. Under optimal conditions, the LODs ranged from 3.0 ng/g to 4.2 ng/g. The recoveries (78.5−103.2%) and relative standard deviations RSDs (<4.6%) of five HAAs were obtained. These are in accordance with the validation criteria (recovery in the range of 70−120% with RSD less than 20%). Compared with conventional clean-up adsorbents (PSA or C18), Fe3O4-MWCNTs displayed equivalent or better matrix removal efficiency, while making the pretreatment process easier and more time-saving through magnetic separation. Less usage of adsorbent makes the method possess another advantage of being lower in cost per sample. The method developed was successfully applied to analyze real samples collected from local deli counters, demonstrating Fe3O4-MWCNTs could be considered as an effective alternative adsorbent with great potential in the QuEChERS process.

Simultaneous analysis of paralytic shellfish toxins and tetrodotoxins in human serum by liquid chromatography coupled to Q-Exactive high-resolution mass spectrometry

Paralytic shellfish toxins (PSTs) and tetrodotoxins (TTXs) are powerful neurotoxins. Previous research reported that PSTs and TTXs are found together in seafoods and may pose a serious hazard to public health. In this study, a new analytical method combining modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) with high-performance liquid chromatography coupled to Q-Exactive Orbitrap high-resolution mass spectrometry was developed and validated for the quantification of 10 PSTs and 2 TTXs in human serum. Chromatographic separation was achieved using the HILIC TSK-Gel Amide-80 column. The mass spectrometer was operated in full scan/dd-MS2(data-dependent MS2) mode, and for quantification analysis. The dd–MS2 resolution was set to 17,500 fullwidthat halfmaximum （FWHM）. Results showed that methanol with 1 % (v/v) acetic acid extraction combined with 50 mg graphitized carbon black (GCB) and 50 mg octadecyl bonded silica gel (C18) was most suitable for purification. The mean recovery for all toxins ranged from 85.3 % to 118.2 % (RSD < 12 %). The limits of detection and quantification for human serum were in the ranges of 0.67–2.61 and 2.23–8.69 ng mL−1, respectively. The method was applied to analyze toxins in serum samples obtained from three poisoned patients in a case of poisoning caused by consumption of toxin-contaminated gastropoda (Bullacta exerata). The study has important application for rapid and accurate diagnosis of PSTs and TTXs toxin poisoning patients in clinic.

Uptake of Soil-Residual Diazinon by Rotational Lettuce under Greenhouse Conditions.

Pesticide residue is an increasing concern in rotational crop practices. The pesticide used for the primary crop may re-enter the secondary crop, thus exceeding pesticide levels set by the positive list system (PLS). As such, evaluation of pesticide residue translocated into rotational crops is required for ensuring pesticide safety. In this study, we investigated the residue pattern of diazinon translocated into lettuce as a typical rotational crop in Korea. Diazinon was used to treat greenhouse soil at the maximum annual application rate before crop planting. Diazinon residues in soil and lettuce were investigated using liquid chromatography/tandem mass spectroscopy and a modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method. The limit of quantitation (LOQ) of diazinon was found as 0.005 mg/kg for the plant and soil samples. The recovery of diazinon at the LOQ and 10× the LOQ ranged from 100.2% to 108.7%. The matrix calibration curve showed linearity, with R2 values &gt; 0.998. Diazinon residue in soil dissipated over time after the initial treatment, generating first-order kinetics (R2 = 0.9534) and having a half-life of about 22 days. The uptake ratio (UTR) of diazinon from the soil to the plant ranged from 0.002 to 0.026 over the harvest period. Considering the UTRs, diazinon residue in the edible leaf could exceed the PLS level (0.01 mg/kg) if lettuce is rotated in soil containing &gt;0.357 mg/kg of diazinon. Based on our findings, to comply with the PLS, a 3-month plant-back interval is required following diazinon treatment and/or setting the maximum residue limit of diazinon for lettuce.

Rapid and simultaneous extraction of phthalates, polychlorinated biphenyls and polycyclic aromatic hydrocarbons from edible oil for GC–MS determination

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method, for reliable semi-quantitative screening of 27 organic contaminants including phthalates (PAEs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry (GC-MS) in edible oil, was developed. N-hexane saturated with acetonitrile and C18-Z-Sep+ was used for extraction and cleanup in liquid liquid extraction-dispersive solid phase extraction (LLE-dSPE) combined with freezing-lipid precipitation. Subsequently, NAGINATA2.0 software with a constructed calibration-locking database was used to detect the organic contaminants and validate the method. The calibration curves were observed to be linear in the range of 0.01–0.5 µg/mL for PAEs and PAHs, and 0.02–1 µg/mL for PCBs. The recoveries for most of the organic contaminants were in range of 70.9–110% with relative standard deviation less than 20%. The proposed method should provide an efficient tool for semi-quantitative screening of numerous organic contaminants in edible oil samples simultaneously.

Chiral separation of new chiral insecticide pyraquinil isomers and establishment of analytical methods in vegetables

以全新手性杀虫剂唑虫酯为研究对象,通过筛选手性色谱柱和优化流动相比例,建立了唑虫酯及其氧化代谢物异构体的拆分方法,在此基础上开发利用高效液相色谱-串联质谱(HPLC-MS/MS)同时测定小白菜和蕹菜中唑虫酯及其氧化产物手性异构体的分析方法。以纤维素-三(3,5-二氯苯基氨基甲酸酯)共价键合手性柱(Chiral INC)(250 mm×4.6 mm, 5 μm)为分析柱,乙腈和2 mmol/L甲酸铵水溶液作为流动相进行梯度洗脱分离,在多反应监测负离子模式下进行检测,唑虫酯4个异构体分离度分别为1.63、2.83和1.74,唑虫酯氧化产物异构体分离度为5.82。通过衍生化的方法进一步确定出峰顺序为RS-唑虫酯、SS-唑虫酯、RR-唑虫酯、SR-唑虫酯、S-唑虫酯氧化产物和R-唑虫酯氧化产物。唑虫酯和其氧化产物的手性异构体分别在1.25~1250 μg/L和2.5~2500 μg/L范围内具有良好的线性关系,相关系数(R2)大于0.99。在蕹菜和小白菜样品中同时添加唑虫酯和唑虫酯氧化产物消旋体进行添加回收试验,添加水平为1、20、400 μg/kg(即唑虫酯异构体为0.25、5、100 μg/kg;唑虫酯氧化代谢产物异构体为0.5、10、200 μg/kg),回收率为72.6%~110.6%,相对标准偏差(RSD)均在9.4%以下,其中日内重复性的RSD在0.5%~9.4%之间;日间重复性的RSD在1.0%~8.6%之间,表明该方法具有良好的回收率和精密度。该研究可为唑虫酯这一新型手性农药的环境行为研究及后续质量控制、药效评价等提供相应的分析技术,为新农药开发应用提供有力的技术支撑。

Methods in food defence: a simple and robust screening for 16 rodenticides by LC-DAD/FLD following QuEChERS–based extraction

Fortunately, the intentional contamination of food or water supplies out of criminal or terroristic motivation is a rather rare event. However, in the face of asymmetric warfare and as the consequences of such an event would be severe, food defence as a necessary supplement to food safety is gaining increased attention. While some progress has been made in developing non-target detection devices, the contamination of food or water supplies using readily available rodenticides may still be revealed only by complex analytical techniques. The presented study therefore aimed to develop a quick and easy screening method for the detection of sixteen globally common rodenticides in foodstuffs. Robust operation with limited personnel and analytical resources were one benchmark to be met by the method, which uses a slightly modified QuEChERS (quick, easy, cheap, effective, rugged, safe) protocol for dispersive solid-phase extraction and subsequent ion-pair chromatography with diode-array and fluorescence detection. Quantification limits were as low as 5 µg/kg with satisfying bias (recovery) and repeatability rates of 77 to 117% and 1.8 to 17.1%, respectively. The developed method provides reliable and robust detection of these deadly poisons at toxic concentrations, which was demonstrated impressively in an improvised assault scenario.

An integrative review on the analysis of pesticide multiresidues in sweet pepper samples using the QuEChERS method and chromatographic techniques

Since foods are complex matrices that contain pesticides of different classes, multiresidue sample preparation methods such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) are used and modified to obtain more accurate and sensitive results. This work was developed through an integrative review in the journal databases Capes, Science Direct, Scielo, and Scientia Chromatographic, from 2011 to 2021, to answer the following question: “What is the most efficient and advantageous sample preparation method for the determination of multiresidue pesticides of interest in sweet pepper samples, when chromatographic techniques are used for detection?” The sweet pepper was chosen because the Pesticide Residue Analysis in Food Program (PARA) suggests that it is the sample with the highest percentage of irregularities related to active ingredients not allowed or above the Maximum Residue Limit (MRL). A total of 391 articles were found, 11 of which met the inclusion criteria established. Several analyses were studied. The organophosphates were the most studied class of pesticide, with seven articles. In addition, there was a predominance of nonpolar analytes (log Kow &gt; 1). The use of different extracting solvents, such as methanol, acetonitrile, ethyl acetate, and acetone, was observed, with acetonitrile presenting the best analytical parameters in most cases. The use of different sorbents such as secondary and primary secondary amine (PSA), ocatadecyllane (C18), graphite carbon (GCB), and carbon black was noted, as well. The authors highlight the difficulties in the analysis when the matrix effect is significant (except for fensulfothion, tensulfothion, flonicamid, and its metabolite TFNA-AM) and the degradation of analytes through the analysis process (flonicamid, captan, folpet, thiophanate methyl and benomyl). Finally, the statistical test Analysis of Variance (ANOVA) was used to identify if there was a significant difference between the different methods used for the same analysis or when the same method used for the different analytes.

Establishment and Validation of Anticoagulant Rodenticides in Animal Samples by HPLC-MS/MS, Focusing on Evaluating the Effect of Modified QuEChERS Protocol on Matrix Effect Reduction.

A rapid, accurate, and selective analytical method to simultaneously quantify 13 anticoagulant rodenticides in animal biological samples was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupled with electrospray ionization (ESI) in negative mode. Samples were extracted and purified based on a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) sample preparation technique. The sample pH and the type of extraction solvent and cleanup sorbent used to estimate the procedure’s effectiveness were optimized. To improve the matrix effects and obtain acceptable recoveries for 13 rodenticides, 0.1 mL/g biological sample and 1 mL acetonitrile (or acetonitrile: EtOAc = 1:1/(v:v)) extraction followed by Florisil/HC-C18/anhydrous Na2SO4 (NaCl) cleanup under alkaline conditions was fully validated and shown to be selective, precise, accurate, and linear in the range from 1 to 100 ng/mL (g). The mean recoveries were between 52.78 and 110.69%, while the limits of detection and quantification ranged from 0.05 to 0.5 and 0.1–1 ng/mL (μg/kg), respectively. Ideal soft matrix effects (≤20%) were observed for the vast majority of rodenticides (>95%) showing either suppression or enhancement. This method meets international criteria and is capable of simultaneously identifying and quantifying anticoagulant rodenticides in animal blood and tissues and can be suitable for the detection of poisoning cases in the field of forensic or public health.

Analysis of popular pesticide residues in Mekong Delta vegetables using a modified QuEChERS method and UPLC-MS/MS

Pesticide residues in vegetables (watercress, mustard green, choy sum, daikon, okra, and yam) from Mekong Delta, Vietnam were analysed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction, matrix-matched calibration, and dynamic multiple reaction monitoring methods were used. The linear range used was 5 - 200 ng/mL, resulting in R2 &gt; 0.99. The recovery was satisfactory with values within 74.47 - 116.93%, and the RSD was &lt; 15% for most compounds. The percentage of samples with residues above the maximum residue levels (MRLs) was 59%. Pesticide residues were detected above their MRLs in samples of watercress (47%), mustard green (80%), choy sum (83%), daikon (87%), and yam (60%). The results indicated the prevalence of pesticide residues in commonly consumed vegetables in Vietnam, and emphasised the urgent need to develop comprehensive intervention measures to reduce the potential health risk to consumers.

Dissipation Behavior and Acute Dietary Risk Assessment of Thiamethoxam and Its Metabolite Clothianidin on Spinach.

Thiamethoxam and its metabolite clothianidin residues pose a potential threat to human health. This study aims to investigate the residue behavior and acute dietary risk assessment of thiamethoxam and clothianidin on spinach. Thiamethoxam and clothianidin were extracted using a quick, easy, cheap, effective, rugged, safe (QuEChERS) method and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At spike levels from 0.01 to 5 mg kg−1, the average recoveries of both analytes were in the range of 94.5–105.5%, with relative standard deviations (RSDs) of 3.8–10.9%. The dissipation behavior of thiamethoxam followed first-order kinetics, with half-lives of ≤1.6 days. Clothianidin appeared readily as a plant metabolite with highest level exhibited during 3 to 5 days after application. Temperature and light may be two main factors for degradation of thiamethoxam. Besides, acute risk assessment of thiamethoxam and clothianidin was evaluated with risk quotients (RQs) <100%, which suggested a low health risk for all consumer groups of Chinese residents.

Simultaneous Determination and Health Risk Assessment of Four High Detection Rate Pesticide Residues in Pu'er Tea from Yunnan, China.

Four pesticides with a high detection rate in Pu’er tea have been determined by a QuEChERS (quick, easy, cheap, effective, rugged, safe) method with multiwalled carbon nanotubes (MWCNTs), and combined ultrahigh-performance liquid chromatography–triple quadrupole linear ion trap-tandem mass spectrometry (UHPLC-QTRAP-MS/MS). MWCNs have been compared with other common purification materials, and found to be superior. The matrix effect was systematically studied, and the results show that the MWCNs can quickly and effectively reduce matrix interference values, which were in the range from −17.8 to 13.8. The coefficients (R2) were greater than 0.99, with the limit of quantification ranging from 0.1 to 0.5 μg/kg, and the recovery rate ranging from 74.8% to 105.0%, while the relative standard deviation (RSD) ranged from 3.9% to 6.6%. A total of 300 samples, taken from three areas in which Yunnan Pu’er tea was most commonly produced, tested for four pesticides. The results show that the detection rate of tolfenpyrad in Pu’er tea was 35.7%, which is higher than other pesticides, and the lowest was indoxacarb, with 5.2%. The residual concentrations of chlorpyrifos, triazophos, tolfenpyrad and indoxacarb ranged from 1.10 to 5.28, 0.014 to 0.103, 1.02 to 51.8, and 1.07 to 4.89 mg/kg, respectively. By comparing with China’s pesticide residue limits in tea (GB 2763-2021), the over standard rates of chlorpyrifos, tolfenpyrad, and indoxacarb were 4.35%, 0.87% and 0%, respectively. The risk assessment result obtained with the hazard quotient (HQ) method shows that the HQ of the four pesticides was far less than one, indicating that the risk is considered acceptable for the four pesticides in Pu’er tea. The largest HQ was found for tolfenpyrad, 0.0135, and the smallest was found for indoxacarb, 0.000757, but more attention should be paid to tolfenpyrad in daily diets in the future, because its detection rate, and residual and residual median were all relatively high.

Validation of the Multiresidue Method Analysis for Pesticides in Bee Honey by UPLC-MS/MS using the Method of Samples Preparation QuEChERS

In this paper we present the results of evaluating the suitability of the developed method for the simultaneous determination of 200 pesticide residues in bee honey using ultraperformance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS). The main stages of extraction of pesticides from the matrix using QuEChERS (Quick Easy Cheap Effective Rugged Safe) sample preparation are described. Appropriate mobile phase composition was used to better identify analytes, internal standards were not applied. The studied list of pesticides is relevant for use in modern agriculture. The limit of quantification of the method (LOQ) for each of the analytes is 0.001 mg/kg, the relative standard deviation in the conditions of repeatability and reproducibility &lt; 20.0 %, the expanded measurement uncertainty is less than the limit of regulatory requirements &lt; 50.0 %. The calibration graph for each of the analytes had a coefficient R2 &gt; 0.99. The use of QuEChERS sample preparation methods allows to reduce labor intensity, time and reagents, increase the accuracy and precision of research in comparison with classical methods of sample preparation. The described method makes it possible to detect a wide range of pesticides and has a fairly high sensitivity

A Rapid, Efficient, Reliable Method for Simultaneous Determination of Pesticide Residues in Green Chilli by Gas Chromatography-Mass Spectrometry

This study describes a rapid, efficient and reliable method for the simultaneous determination of 42 pesticide residues in green chilli using gas chromatography single quadrupole mass spectrometry with selected ion monitoring (GC-SQ/MS-SIM) mode. QuEChERS (quick-easy-cheap-effectiverugged- safe) acetonitrile-based extraction technique was used prior to GC-MS analysis, followed by cleanup with primary-secondary amine (PSA). Linearity (r2 &gt; 0.99) within 50-1000 μg/kg with negligible matrix interferences was achieved by method optimization. The percentage recovery evaluated at 50, 100 and 250 μg/kg level of spiked concentration was observed to range between 75-127% with RSD (&lt; 9.1%) for the majority of analytes. The expanded uncertainty was measured below 48% for all target residues. The limit of detection and limit of quantification ranged between 1-63 μg/kg and 4-150 μg/kg, respectively. The developed method was observed to be specific, accurate, reproducible and user friendly for determining different pesticides in green chilli crops.

Determination of bongkrekic acid in tremella and auricularia auricular by improved QuEChERS method combined with ultra-high performance liquid chromatography-triple quadrupole mass spectrometry

采用改良的QuEChERS方法,结合超高效液相色谱-串联质谱(UHPLC-MS/MS)建立了银耳和木耳中米酵菌酸含量测定的分析方法。对QuEChERS方法的提取、净化条件进行了优化,发现提取液中乙酸含量对米酵菌酸的提取效率影响很大,最终采用5%(v/v)乙酸乙腈为提取溶剂,盐析分层,再用200 mg C18分散固相萃取净化。对UHPLC-MS/MS分析条件也进行了优化,以含0.01%(v/v)甲酸、0.05%(v/v)氨水的水溶液和甲醇为流动相,在Waters HSS T3柱(100 mm×2.1 mm, 1.8 μm)上分离,以电喷雾电离、多反应监测负离子模式进行检测。在优化好的条件下,银耳和木耳中米酵菌酸检测的基质效应分别为-6.3%和-11.5%,表明该方法具有很好的净化效果,样品基质不会对米酵菌酸的检测产生影响。进一步对方法学进行了考察,在1~200 μg/L范围内,线性方程回归系数的平方(R2)大于0.999,以信噪比的3倍和10倍计算的方法检出限和定量限分别为0.15 μg/kg和0.5 μg/kg。银耳中3种添加水平0.5、10、50 μg/kg下的加标回收率为92.4%~102.6%,日内和日间相对标准偏差(RSD)分别为4.3%~4.9%和3.2%~3.5%;木耳的加标回收率为89.6%~102.3%,日内和日间RSD分别为2.4%~9.5%和3.6%~4.1%,表明该方法具有很好的准确度和精密度。最后,将该方法应用于实际样品中米酵菌酸的分析,取得了很好的效果。该工作为银耳和木耳中米酵菌酸的风险防控提供了一种有效的检测技术。

Monitoring of Pesticide Residues in Imported Datepalm Fruits in United Arab Emirates

The occurrence of pesticide residues in representative samples collected from imported dates palm fruits during 2020 to United Arab Emirates (UAE) was investigated to ensure compliance with the standard specifications and requirements by the regulatory and supervisory authorities, maintain the health and safety of consumers and improve food safety. An accurate, rapid, and reliable method for the simultaneous determination of pesticide multi-residues in 230 samples imported dates by liquid chromatography coupled with tandem mass spectrometry (LC–ESI (+)-MS/MS) operating in multiple reaction monitoring (MRM) mode and modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method was used. The performance of the analytical method was validated in accordance with EU SANCO guidelines (SANTE/12682/2019) for monitoring pesticide multi-residues to check compliance with existing regulations, especially for European Community. Residues level of 343 compounds were determined in 230 samples. Results indicated that the percentage of samples with residues above the maximum residue levels (MRL) was 4.34% in dates samples, whereas samples with residues within MRL were 7.39% in dates samples. A total of 230 samples of 88.26% were free from detectable residues. Out of the 343 pesticides tested, 11 pesticides were found above the limit of detection, according to UAE, Codex, and European regulations. The main purpose of this work is to inform citizens and traders who have concerns about food safety on the capability of the MOCCAE on quality assurance regarding pesticide residue in imported food.

A fluorinated chitosan-based QuEChERS method for simultaneous determination of 20 organophosphorus pesticide residues in ginseng using GC-MS/MS.

In this study, a new fluorinated methacrylamide (MACF) was synthesized and evaluated as an adsorbent in the dispersive solid-phase extraction for the effective determination and extraction of 20 organophosphorus pesticides (OPPs) from ginseng samples using the QuEChERS (quick, easy, cheap, effective, rugged, safe) method coupled with GC-MS/MS. The properties of MACF were characterized using Fourier-transform infrared spectroscopy, elemental analysis, and high-resolution 19 F NMR. MACF, chitosan, primary and secondary amine, octadecylsilane, graphitized carbon black, Z-Sep, Z-Sep+ , and EMR-Lipid were compared in terms of extraction efficiency. The best results were obtained when MACF was used. Matrix-matched calibration was employed for quantification. All the OPPs exhibited good linearity (r2 > 0.9969) with the concentration at their respective concentration ranges. The limits of detection were 1.5-3.0μg/kg, and the limits of quantification were 5.0-10.0μg/kg. The trueness of the 20 pesticides at four spiked levels ranged from 86.1 to 111.1%, and the relative standard deviation was less than 11.3%. The modified QuEChERS method using MACF as the adsorbent was sensitive, reliable, and cost-effective and could be used for the determination of 20 OPP residues in ginseng.

DISSIPATION OF CYFLUMETOFEN IN STRAWBERRY FRUITS AND GREEN BEAN PODS UNDER GREENHOUSE CONDITIONS USING QUECHERS METHOD AND GC/(μ-ECD)

Strawberry and green bean are important cash crops. Both are highly infected by different pests under greenhouse conditions causing reduction in quality and yield. Mites are usually from the most common pests of beans and strawberries. Field experiment was carried out to investigate dissipation of Cyflumetofen (a novel acaricide) in strawberry fruits and green bean pods. Determination was done using quick, easy, cheap, effective, rugged, safe (QuEChERS) method and cleanup step utilizing dispersive solid-phase extraction (DSPE) followed by gas chromatography coupled with a micro electron capture detector GC/(μ-ECD). Average recoveries were within 80.75-92.15% and 80.86-82.91%, with relative standard deviations (RSDs) ranging from 2.8 to 6.6% and 3.59-4.70%. in strawberry and green bean samples, respectively at spiking levels (0.01 - 1 mg/kg). Linearity was achieved for Cyflumetofen with correlation coefficient R2 > 0.98 and matrix-matched calibration also showed linearity with determination coefficients R2 > 0.98. The initial deposits in strawberry fruits and green bean pods were 2.48 and 3.24 mg/kg, respectively. The half-life period (RL50) in strawberry fruits and green bean pods was 1.81 and 1.16 days, respectively. According to maximum residue level (MRL) which is 0.6 mg/kg, the pre-harvest interval (PHI) was estimated to be 3 days in strawberry fruits.

Determination of Pydiflumetofen Residues in Rice and its Environment by an Optimized QuEChERS Method Coupled with HPLC-MS.

Pydiflumetofen is a new succinate dehydrogenase inhibitor fungicide, and the method for determination of its residues in rice and associated environmental samples has not yet been reported. Here, we optimized, Quick Easy, Cheap, Effective, Rugged, Safe (QuEChERS) method for sample preparation, and used high performance liquid chromatography-tandem mass spectrometry (HPLC-MS) to detect the residual amounts of pydiflumetofen in rice and its environment. The results showed that there was a good linearity over the pydiflumetofen concentration range of 0.01-0.1mg/L in all matrices (R2 > 0.99). At the spiked levels of 0.01, 0.05, and 0.1mg/kg, the recovery rates of pydiflumetofen from various matrices were between 84.23 and 105.10 %, with the relative standard deviation of 1.07-9.99 %. The limit of detection (signal-to-noise ratio = 3) of the proposed method for pydiflumetofen was in the range of 1.9-3.5µg/kg, and the limit of quantification (signal-to-noise ratio = 10) was in the range of 6.3-11.7µg/kg.

Impact of Photolysis and TiO2 on Pesticides Degradation in Wastewater

Pesticide residues are harmful to the environment and human and animal health even at low levels because of long-term bioaccumulation. In this study, photolysis was applied to treat three representative water samples: aqueous atrazine and dimethoate solutions as target pesticides, as well as wastewater and agriculture wastewater containing pesticide residue. It was performed using ultraviolet (UV) irradiation at two wavelengths (254 and 306 nm) with exposure times ranging from 2 to 12 h in the presence and absence of a photocatalyst to identify the optimal degradation conditions. Extraction and analyzation process were performed by the Quick Easy Cheap Effective Rugged Safe (QuEChERS) methods and gas chromatography–tandem mass spectrometry with triple quadrupole detector (GC–MSMS/TQD), respectively. Photodegradation increased with an increase in exposure time and the TiO2 catalyst was beneficial for degradation. Both selected irradiation wavelengths were effective, although the wavelength of λ = 306 nm was the most efficient.

Development and validation of an LC-MS/MS screening method for macrolide and quinolone residues in baby food

A simple, rapid and sensitive screening method by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the identification of 7 macrolides (clarithromycin, erythromycin, oleandomycin, spiramycin, tilmicosin, troleandomycin and tylosin) and 8 quinolones (ciprofloxacin, difloxacin, enrofloxacin, flumequine, moxifloxacin, nalidixic acid, norfloxacin and ofloxacin) in meat and egg-based baby foods. Sample preparation was performed using an alkaline modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction method without additional clean-up steps. A simplex-lattice mixture experimental design was used in the optimization of the QuEChERS extraction solvent. The developed method was successfully validated according to the Commission Decision 2002/657/EC and the European Community Reference Laboratories Residues Guidelines regarding the validation of screening methods 20/01/2010, adopting a fixed permited tolerance for relative ion ratio. Samples of baby food (n = 44) commercialized in Rio de Janeiro, Brazil, were analyzed using the validated method and none of them presented residues of the searched macrolides and quinolones, with a screening target value of 5 µg kg−1.