Multiresidue Method for the Rapid Determination of Pesticide Residues in Tea Using Ultra Performance Liquid Chromatography Orbitrap High Resolution Mass Spectrometry and In-Syringe Dispersive Solid Phase Extraction

Simultaneous Screening and Quantification of 479 Pesticides in Green Tea by LC-QTOF-MS

A high-throughput screening and quantification method for 479 pesticides in green tea was established based on solid-phase extraction combined with liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Pesticides were extracted from samples using an optimized SPE (TPT cartridges) procedure. LC-QTOF-MS in All Ions MS/MS scan mode acquired full MS data for quantification and product ion spectra for identification. LC-QTOF-MS quantification was achieved using matrix-matched standard calibration curves to achieve the optimal method accuracy. The method performance characteristics included the linearity, overall recovery, precision, and measurement uncertainty being evaluated. The validation results exhibited a good sensitivity with the LOQs of 5-55 µg/kg, which was satisfactory for their MRLs in China or the EU. The recoveries of more than 92.7% of the 479 pesticides in green tea were 70-120% at the three spiked levels with a precision of ≤20%. Finally, this method was employed to analyze 479 pesticides in 95 tea samples from markets in China. The test results of the tea samples showed that tolfenpyrad, buprofezin, and pyridaben were found with lower concentrations. The method has effectively improved the determination efficiency of pesticide residue screening by high-resolution mass spectrometry in green tea.

Simultaneous monitoring and dietary risk assessment of 386 pesticides in market samples of black tea

Black tea samples (390) collected from local markets situated in different locations of India were monitored for the residues of 386 pesticides using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) based extraction and analysis by gas and liquid chromatography tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Residues of seventeen pesticides were detected, of which propargite, cypermethrin, and novaluron showed the highest % positive detections. A comparison of the concentrations of the detected pesticide residues with the available national and international maximum residue limits (MRLs) showed that seven samples exceeded the Indian MRLs while no sample was found to exceed the CODEX MRLs. The risk due to the detected pesticide levels evaluated in terms of hazard quotient (HQ) and hazard index (HI) was found to be very low (<1), suggesting that the pesticide residues in the tea were safe for consumption by Indian adults and children.

A liquid chromatographic method for determination of acetamiprid and buprofezin residues and their dissipation kinetics in paddy matrices and soil

The present study was conducted to investigate the residue status of two insecticides (acetamiprid and buprofezin) and their dissipation kinetics in three matrices viz. paddy grain, straw, and soil. The extraction procedure for residues of these two insecticides was executed using acetonitrile solvent. The analytical method was validated, which showed good linearity with the limit of quantification (LOQ) value of 0.01 and 0.02 mg kg^-1 for acetamiprid and buprofezin, respectively. The recovery range was 79.67-98.33 % concerning all the matrices in both the insecticides. Acetamiprid (20% SP) and Buprofezin (25% SC) were applied separately in the paddy field in two doses: single dose (recommended dose) and double dose along with untreated control throughout the experiment. Residue analysis of these two insecticides in paddy (grain and straw) and soil was accomplished employing high-performance liquid chromatography (HPLC) with ultraviolet (UV) detector and confirmed by ultra-performance liquid chromatography (UPLC) coupled with mass spectrometry (UPLC-MS/MS). The dissipation data showed that acetamiprid exhibited higher dissipation in comparison with buprofezin. However, their persistence was found slightly higher in soil. The dissipation dynamics in the rice and soil were discussed with biological half-lives of both the insecticides. Consumer risk assessment study was also made considering its fate to the consumers.

Neonicotinoid residues in commercial Japanese tea leaves produced by organic and conventional farming methods

The current study sought to assess the residual levels of neonicotinoid insecticides (NEO) in organic and conventional green tea leaves produced in Japan. A total of 103 tea leaves (thus, 42 organic and 61 conventional), were sampled from grocery stores in Japan. Concentrations of NEOs in the tea leaves were quantified using LC–MS/MS; and the data was used to estimate maximum daily intakes of NEOs within the Japanese population. Seven native NEO compounds and one NEO metabolite were detected in both organic and conventional tea leaves. Detection frequencies (%Dfs) of NEOs in the tea samples (n = 103) were found in the decreasing order; thiacloprid (84.47 %) > dinotefuran (74.76 %) > imidacloprid (69.90 %) ≈ clothianidin (69.90 %) > dm-acetamiprid (63.11 %) > thiamethoxam (58.25 %) > acetamiprid (4.85 %) > nitenpyram (1.94 %). About 94.20 % of the tea leaves contained two or more NEO compounds simultaneously. The %Dfs of NEOs were relatively lower in organic tea leaves, compared to the conventional tea leaves. Various percentile concentrations of NEOs were far lower in organic tea leaves, compared to the conventional tea leaves. The maximum daily intakes of NEOs through consumption of tea (MDIgt) were also lower for organic tea leaves, compared to the conventional tea samples.

Dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction for the determination of some pesticides in molasses samples

In this study, a sensitive analytical method was developed to determine some pesticides (cyprodinil, trifloxystrobin, prometryn, propachlor, fenitrothion, chlorpyrifos, profenofos, and phosalone) in molasses samples. Pesticides were extracted from samples by dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction and determined by gas chromatography-mass spectrometry analysis. In this method, pesticides in molasses samples were first extracted using a water-miscible solvent (acetonitrile) in the sugaring-out homogeneous liquid-liquid extraction stage. The sugar in the ratio of 84-88% naturally contained in the molasses sample enabled phase separation in the acetonitrile-water homogeneous mixture. Then acetonitrile phase containing pesticides was used as dispersing solvent in the second step of the process. Under the specified optimum conditions, the limit of detection was calculated between 0.8-6.1 ng/g and the limit of quantification was in the range of 2.5-20 ng/g. The relative standard deviation values of molasses samples containing 150 ng/g of each analyte were found to be lower than 4.9% intra-day and 5.6% for inter-day. This validated method has been successfully applied to different types of molasses.

Nontarget and high-throughput screening of pesticides and metabolites residues in tea using ultra-high-performance liquid chromatography and quadrupole-orbitrap high-resolution mass spectrometry

A Sin-QuEChERS, coupled to UHPLC Q-Exactive Orbitrap MS, was used for nontargeted high-throughput rapid screening and quantitative analysis of residual pesticides and metabolites in green teas. The sample was extracted with 0.1% formic acid in acetonitrile with shaking, salted out and centrifuged, and purified with Sin-QuEChERS Nano solid phase extraction column; with Full MS/ddMS2 as the data collection mode, the database containing 384 pesticides combined with Trace Finder 3.0 software, In the absence of standard products, rapid screening and confirmation of potential pesticide residues in tea samples with accurate mass, isotope abundance ratio, secondary fragment ions, etc. 20 pesticides were used as quality controls to verify the screening method, and the linearity of these pesticides was between 1 and 200 μg/L, and the correlation coefficients were all greater than 0.9922. Moreover, the LOQ was between 0.002 and 0.01 mg/kg. The average recoveries of spiked tea samples were 74%-111%. Efficiency and reliability of this method were investigated by the analysis of 38 Chinese green tea samples. 18 potential residual pesticides were detected by non-targeted screening. The researchers then conducted a quantitative analysis of the 18 potential residual pesticides.

Simultaneous determination of 14 pesticide residues in tea by multi-plug filtration cleanup combined with LC-MS/MS

A combined method of multi-plug filtration cleanup (m-PFC) and liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) was established to simultaneously detect 14 pesticides in tea. The pesticides in water-soaked tea were extracted with acetonitrile. Cleanup of tea extract was performed using an m-PFC column packed with multiple cleanup materials: multi-walled carbon nano-tubes (MWCNTs), primary secondary amine (PSA) and anhydrous magnesium sulfate (MgSO₄). The cleanup effect of the column was evaluated based on the rates of removal of tea components that interfered with pesticide recovery, henceforth referred to as interference components. Results showed that 14 pesticides had strong linearity in the range of 5-500 μg L^-1 (r² > 0.99). The quantitative limits were within the range of 3-50 μg kg^-1. The average recoveries of 14 pesticides spiked into three different blank tea samples (green tea, black tea, oolong tea) at three levels of 0.05, 0.50 and 2.00 mg kg^-1 were in the range of 62.3-108.8% with relative standard deviations of 0.2-13.6%. The m-PFC method can greatly improve the efficiency of sample pretreatment. Furthermore, this work provides methodological guidance on how to select cleanup materials and allocate their proportions.

A novel sample-preparation method for the generic and rapid determination of pesticides and mycotoxins in tea by ultra-performance liquid chromatography-tandem mass spectrometry

A rapid, simple, and generic analytical method for the simultaneous determination of 140 undesirable low-weight pesticides and mycotoxins from different chemical classes in black tea was developed. The method involved swelling the sample in ammonium acetate buffer, extraction with acetonitrile-dimethyl sulfoxide, cleanup by dual dispersive solid-phase extraction (D-SPE) with the assistance of low-temperature centrifugation, and analysis by ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry using multiple reaction monitoring mode. The interferences in the extract were eliminated by the combination of dual d-SPE using only C₁₈ sorbent and anhydrous magnesium sulfate, which maintained the chromatographic column under the ideal condition for a long time and enabled satisfactory recoveries of hydrophobic and hydrophilic analytes simultaneously. Matrix-matched calibration curves were obtained for most target compounds with linear regression coefficients above 0.9900. The limits of quantification (LOQs) ranged within 0.5-10.0 μg/kg, which were usually sufficient to verify the compliance of products with legal tolerances. Satisfactory recoveries of 64.5%-138.1% were obtained in black ta samples with the relative standard deviation (RSD) values between 1.8 and 25.9%. The inter-day precision ranged within 2.2%-24.9%. For over 90% of the analytes, the recoveries were between 70% and 120%, with RSD values below 15.0%. The application of this method in routine monitoring programs can drastically reduce effort and time.

Technical Overview of Orbitrap High Resolution Mass Spectrometry and Its Application to the Detection of Small Molecules in Food (Update Since 2012)

Food safety and quality issues are becoming increasingly important and attract much attention, requiring the development of better analytical platforms. For example, high-resolution (especially Orbitrap) mass spectrometry simultaneously offers versatile functions such as targeted/non-targeted screening while providing qualitative and quantitative information on an almost unlimited number of analytes to facilitate routine analysis and even allows for official surveillance in the food field. This review covers the current state of Orbitrap mass spectrometry (OMS) usage in food analysis based on research reported in 2012-2019, particularly highlighting the technical aspects of OMS application and the achievement of OMS-based screening and quantitative analysis in the food field. The gained insights enhance our understanding of state-of-the-art high-resolution mass spectrometry and highlight the challenges and directions of future research.

Determination of thirteen acidic phytohormones and their analogues in tea (Camellia sinensis) leaves using ultra high performance liquid chromatography tandem mass spectrometry

Trace plant hormones play an important role in tea growth, development and quick response to biotic and abiotic stresses. However, lack of a sensitive method limits the research on plant hormone regulation for tea quality and yields. Herein, a highly sensitive method was developed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for profiling and quantification of 13 acidic phytohormones and their analogues, including auxins, abscisic acid and gibberellins in fresh tea leaves. After optimizing the different C18 columns and mobile phase systematically, an Agilent Eclipse Plus C18 column combined with the mobile phase A (acetonitrile) and B (water) was employed. Target acidic phytohormones were extracted using acidified methanol, and tea matrices were cleaned up by dispersive solid phase adsorbents of polyvinylpolypyrrolidone (PVPP) and graphitized carbon black (GCB) followed by polymer-based mixed-mode cation-exchange solid phase extraction. The method showed good linearity for all 13 analytes with regression coefficients (R²) > 0.998. Satisfactory recoveries of 12 analytes spiked with three levels ranged from 71.8% to 109.9%, while intra-day and inter-day precisions were below 20%. Limits of detection (LODs) and limits of quantitation (LODs) for 12 acidic phytohormones were 0.1-4.2 μg kg^-1 and 0.3-13.9 μg kg^-1, respectively. Finally, this method was firstly employed to analyze 13 analytes in fresh tea leaves (with the treatment of dormancy, light qualities, exogenous hormones and infestation of pests), highlighting its sufficient capability for rapid analysis of multiclass phytohormones in agriculture field.

The use of fast molecular descriptors and artificial neural networks approach in organochlorine compounds electron ionization mass spectra classification

Developing of theoretical tools can be very helpful for supporting new pollutant detection. Nowadays, a combination of mass spectrometry and chromatographic techniques are the most basic environmental monitoring methods. In this paper, two organochlorine compound mass spectra classification systems were proposed. The classification models were developed within the framework of artificial neural networks (ANNs) and fast 1D and 2D molecular descriptor calculations. Based on the intensities of two characteristic MS peaks, namely, [M] and [M-35], two classification criterions were proposed. According to criterion I, class 1 comprises [M] signals with the intensity higher than 800 NIST units, while class 2 consists of signals with the intensity lower or equal than 800. According to criterion II, class 1 consists of [M-35] signals with the intensity higher than 100, while signals with the intensity lower or equal than 100 belong to class 2. As a result of ANNs learning stage, five models for both classification criterions were generated. The external model validation showed that all ANNs are characterized by high predicting power; however, criterion I-based ANNs are much more accurate and therefore are more suitable for analytical purposes. In order to obtain another confirmation, selected ANNs were tested against additional dataset comprising popular sunscreen agents disinfection by-products reported in previous works.

The determination of pesticides in tea samples followed by magnetic multiwalled carbon nanotube-based magnetic solid-phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry

A simple and efficient method regarding ultrasound-assisted extraction combined with magnetic solid-phase extraction (UA-MSPE) by UHPLC-MS/MS was set up for the determination of three pesticides in tea leaf samples.

A novel high-performance liquid chromatography-fluorescence analysis coupled with in situ degradation-derivatization technique for quantitation of organophosphorus thioester pesticide residues in tea

A novel high-performance liquid chromatography-fluorescence analysis in combination with in situ degradation-derivatization (ISD-D) technique was developed for simultaneous determination of seven organophosphorus thioester pesticides (OPTPs) in tea. The ISD-D technique was based on degradation of OPTPs by a nucleophilic substitution reaction between phenylbutane-1,2,3-trione-2-oxime and OPTPs, which can give thiol degradation products (DPs). The thiol DPs obtained were derivatized with the novel derivatization reagent N-(4-(carbazole-9-yl)-phenyl)-N-maleimide (NCPM) in a syringe. Attractively, NCPM itself did not fluoresce, whereas the derivatives of the thiol DPs fluoresced intensely, with excitation and emission maxima at 290 nm and 368 nm, respectively, which extraordinary reduced the background interference and increased the detection sensitivity for thiol DPs. Excellent linearity (R² > 0.995) for all OPTPs was achieved, with limits of detection and limits of quantitation ranging from 0.23 to 0.45 μg/kg and from 0.75 to 1.43 μg/kg, respectively. Satisfactory recoveries ranging from 90.5% to 96.0% were obtained for all OPTPs. The ISD-D technique provided a novel and sensitive strategy for quantitation of trace amounts of OPTPs in real samples. Graphical abstract ᅟ.