Analysis of pesticide residues in tuber crops using pressurised liquid extraction and gas chromatography-tandem mass spectrometry

Method development and validation in the curry leaf matrix employing advanced mass spectrometry: quantitative screening of 490 multiclass pesticides by buffered ethyl acetate technique

Curry leaf is an evergreen herb with culinary, pharmaceutical, and nutraceutical applications. As pesticide residue in curry leaf has garnered significant regulatory attention in recent years, here we report a reliable method, which was validated for the determination of 265 and 225 pesticides using LC-MS/MS and GC-MS/MS, respectively. At first, the sample was comminuted after adding water (1:2). The sample preparation workflow included extraction of 10 g homogenized sample with 10 mL ethyl acetate (+1% acetic acid), cleanup by dispersive solid phase extraction (d-SPE, 50 mg PSA + 50 mg C₁₈ + 10 mg GCB + 150 mg Na₂SO₄) and the final analysis by tandem mass spectrometry. The cleanup step adeptly removed co-extractives. The method effectively reduced matrix effects and offered an LOQ of 0.01 mg kg^-1 for most compounds. The method's accuracy and precision results fulfilled the requirements of SANTE/11312/2021 guidelines at 0.01 mg kg^-1 and higher levels of fortification. The accuracy and precision results were comparable for all pesticides. The successful screening of market samples indicates its high extraction efficiency and precision for incurred residue analysis. Due to its robustness and conformity with regulatory criteria, food testing laboratories worldwide can use the method to monitor pesticide levels in curry leaves.

Pressurized Liquid Extraction: A Powerful Tool to Implement Extraction and Purification of Food Contaminants

Pressurized liquid extraction (PLE) is considered an advanced extraction technique developed in the mid-1990s with the aim of saving time and reducing solvent with respect to traditional extraction processes. It is commonly used with solid and semi-solid samples and employs solvent extraction at elevated temperatures and pressures, always below the respective critical points, to maintain the solvent in a liquid state throughout the extraction procedure. The use of these particular pressure and temperature conditions changes the physicochemical properties of the extraction solvent, allowing easier and deeper penetration into the matrix to be extracted. Furthermore, the possibility to combine the extraction and clean-up steps by including a layer of an adsorbent retaining interfering compounds directly in the PLE extraction cells makes this technique extremely versatile and selective. After providing a background on the PLE technique and parameters to be optimized, the present review focuses on recent applications (published in the past 10 years) in the field of food contaminants. In particular, applications related to the extraction of environmental and processing contaminants, pesticides, residues of veterinary drugs, mycotoxins, parabens, ethyl carbamate, and fatty acid esters of 3-monochloro-1,2-propanediol and 2-monochloro-1,3-propanediol from different food matrices were considered.

Advanced visual sensing techniques for on-site detection of pesticide residue in water environments

Pesticide usage has increased to fulfil agricultural demand. Pesticides such as organophosphorus pesticides (OPPs) are ubiquitous in world food production. Their widespread usage has unavoidable detrimental consequences for humans, wildlife, water, and soil environments. Hence, the development of more convenient and efficient pesticide residue (PR) detection methods is of paramount importance. Visual detecting approaches have acquired a lot of interest among different sensing systems due to inherent advantages in terms of simplicity, speed, sensitivity, and eco-friendliness. Furthermore, various detections have been proven to enable real-life PR surveillance in environment water. Fluorometric (FL), colourimetric (CL), and enzyme-inhibition (EI) techniques have emerged as viable options. These sensing technologies do not need complex operating processes or specialist equipment, and the simple colour change allows for visual monitoring of the sensing result. Visual sensing techniques for on-site detection of PR in water environments are discussed in this paper. This paper further reviews prior research on the integration of CL, FL, and EI-based techniques with nanoparticles (NPs), quantum dots (QDs), and metal-organic frameworks (MOFs). Smartphone detection technologies for PRs are also reviewed. Finally, conventional methods and nanoparticle (NPs) based strategies for the detection of PRs are compared.

Routine analysis of pesticides in foodstuffs: Emerging ambient ionization mass spectrometry as an alternative strategy to be on your radar

Pesticides residues in foodstuffs are longstanding of great concern to consumers and governments, thus reliable evaluation techniques for these residues are necessary to ensure food safety. Emerging ambient ionization mass spectrometry (AIMS), a transformative technology in the field of analytical chemistry, is becoming a promising and solid evaluation technology due to its advantages of direct, real-time and in-situ ionization on samples without complex pretreatments. To provide useful guidance on the evaluation techniques in the field of food safety, we offered a comprehensive review on the AIMS technology and introduced their novel applications for the analysis of residual pesticides in foodstuffs under different testing scenarios (i.e., quantitative, screening, imaging, high-throughput detection and rapid on-site analysis). Meanwhile, the creative combination of AIMS with high-resolution mass analyzer (e.g., orbitrap and time-of-flight) was fundamentally mentioned based on recent studies about the detection and evaluation of multi-residual pesticides between 2015 and 2021. Finally, the technical challenges and prospects associated with AIMS operation in food industry were discussed.

Rapid Screening of 350 Pesticide Residues in Vegetable and Fruit Juices by Multi-Plug Filtration Cleanup Method Combined with Gas Chromatography-Electrostatic Field Orbitrap High Resolution Mass Spectrometry

A new method for screening pesticide residues in vegetable and fruit juices by the multi-plug filtration cleanup (m-PFC) method combined with gas chromatography-electrostatic field orbitrap high resolution mass spectrometry(GC-Orbitrap/MS) was developed. The samples were extracted with acetonitrile, purified with m-PFC and determined by GC-Orbitrap/MS. Qualitative analysis was confirmed by retention time, accurate molecular mass and quantitative analysis were performed with the matrix standard calibration. It could eliminate matrix interference effectively. Eight kinds of typical samples (orange juice, apple juice, grape juice, strawberry juice, celery juice, carrot juice, cucumber juice, tomato juice) were evaluated. The linear ranges of the 350 pesticides were from 5 to 500 μg/kg, with good correlation coefficients greater than 0.990. The limits of detection (LODs) were 0.3-3.0 μg/kg and the limits of quantification (LOQs) were 1.0-10.0 μg/kg. The average recoveries at three spiked levels of 10, 100, 200 μg/kg were in the range of 72.8-122.4%, with relative standard deviations (RSDs) of 2.0-10.8%. The method has effectively improved the determination efficiency of pesticide residue screening by high-resolution mass spectrometry in vegetable and fruit juices.

Efficient enrichment and analysis of atrazine and its degradation products in Chinese Yam using accelerated solvent extraction and pipette tip solid-phase extraction followed by UPLC-DAD

The Chinese Yam (Dioscorea opposita) is cultivated widely in China. However, there are potential safety risks associated with herbicide residues in Chinese Yam because of its characteristics and unregulated use of pesticides. We developed an efficient sample preparation technique for simultaneous analysis of atrazine and its degradation products in Chinese Yam using accelerated solvent extraction and pipette tip solid-phase extraction followed by UPLC-DAD analysis. Molecularly imprinted polymer (MIP) were used as the adsorbent material. Method performance was evaluated and our results showed the limit of quantification was 1-3 μg/ kg, with recoveries in the range 79.2-103.8%. When compared with other methods, this method provided superior performance in terms of sensitivity, accuracy, and precision. This method is, therefore, expected to be useful in supervised residue analysis.

Rapid simultaneous adsorption and SERS detection of acid orange II using versatile gold nanoparticles decorated NH2-MIL-101(Cr)

Acid orange II (AO II), a typical azo pigment, is strictly controlled by legislation and prohibited in foodstuffs. Herein, we prepared gold nanoparticles decorated amino-functionalized Cr-based metal-organic frameworks [NH₂-MIL-101(Cr)@Au] via an in-situ reduction method as a surface-enhanced Raman scattering (SERS) substrate for simultaneous adsorption and detection of AO II. Gold nanoparticles are uniformly dispersed on the surface of NH₂-MIL-101(Cr) owing to its three-dimensional (3D) structure and the interaction between -NH₂ and Au ions, providing more SERS-active "hot spots". These NH₂-MIL-101(Cr)@Au nanocomposites exhibited selective and high adsorption performance (419.85 mg g^-1) for AO II, and could be used as superior SERS substrates for the detection of AO II with a low limit of detection (LOD) of 0.05 mg L^-1 and wide detection range of 0.05-50 mg L^-1 using portable Raman spectrometer. Furthermore, this SERS assay has been successfully used to determine AO II in orange juice and chili powder with good sensitivities.

Analytical methods to analyze pesticides and herbicides

Presented in this paper is an annual review of literatures published in 2018 on topics relating to analytical methods for pesticides and herbicides. According to the different techniques, this review is divided into six sections, including extraction methods; chromatographic or mass spectrometric techniques; electrochemical techniques; spectrophotometric techniques; chemiluminescence and fluorescence methods; and biochemical assays. PRACTITIONER POINTS: Totally 134 relevant research articles are summarized. The review is divided into six parts according to the techniques. Chromatographic and mass spectrometric methods are the most widely used.

What are the Main Sensor Methods for Quantifying Pesticides in Agricultural Activities? A Review

In recent years, there has been an increase in pesticide use to improve crop production due to the growth of agricultural activities. Consequently, various pesticides have been present in the environment for an extended period of time. This review presents a general description of recent advances in the development of methods for the quantification of pesticides used in agricultural activities. Current advances focus on improving sensitivity and selectivity through the use of nanomaterials in both sensor assemblies and new biosensors. In this study, we summarize the electrochemical, optical, nano-colorimetric, piezoelectric, chemo-luminescent and fluorescent techniques related to the determination of agricultural pesticides. A brief description of each method and its applications, detection limit, purpose—which is to efficiently determine pesticides—cost and precision are considered. The main crops that are assessed in this study are bananas, although other fruits and vegetables contaminated with pesticides are also mentioned. While many studies have assessed biosensors for the determination of pesticides, the research in this area needs to be expanded to allow for a balance between agricultural activities and environmental protection.

Simultaneous determination of 25 pesticides in Zizania latifolia by dispersive solid-phase extraction and liquid chromatography-tandem mass spectrometry

An improved quick, easy, cheap, effective, rugged, and safe (QuEChERS) method combined with ultrapressure liquid chromatography tandem mass spectrometric method (UPLC-MS/MS) was developed to simultaneously determine 25 pesticides in Zizania latifolia. The samples were extracted with methanol(MeOH) and 0.1% formic acid (80:20, v/v) and cleaned with C₁₈ absorbent and primary-secondary amine (PSA). LC separation was performed on a BEH C₁₈ UPLC column under the condition of gradient elution with the mobile phase consisted of 0.5% formic acid (10 mM ammonium acetate)/MeOH. External standard calibration method with matrix-matched was used for quantification, and good linearity was obtained over a concentration range of 0.5–100 μg/l, with correlation coefficients greater than 0.9901. The limit of detection (LOD) and the limit of quantitation (LOQ) of the 25 pesticides were in the range of 0.2–1.0 µg/kg and 0.5–3.3 µg/kg, respectively. The recoveries ranged from 72% to 118%, and the relative standard deviations (RSDs) were less than 20%. Thus, the proposed method is suitable for the simultaneous determination of 25 pesticides in Z. latifolia.

Nontargeted Detection Methods for Food Safety and Integrity

Nontargeted workflows for chemical hazard analyses are highly desirable in the food safety and integrity fields to ensure human health. Two different analytical strategies, nontargeted metabolomics and chemical database filtering, can be used to screen unknown contaminants in food matrices. Sufficient mass and chromatographic resolutions are necessary for the detection of compounds and subsequent componentization and interpretation of candidate ions. Analytical chemistry–based technologies, including gas chromatography–mass spectrometry (GC-MS), liquid chromatography–mass spectrometry (LC-MS), nuclear magnetic resonance (NMR), and capillary electrophoresis–mass spectrometry (CE-MS), combined with chemometrics analysis are being used to generate molecular formulas of compounds of interest. The construction of a chemical database plays a crucial role in nontargeted detection. This review provides an overview of the current sample preparation, analytical chemistry–based techniques, and data analysis as well as the limitations and challenges of nontargeted detection methods for analyzing complex food matrices. Improvements in sample preparation and analytical platforms may enhance the relevance of food authenticity, quality, and safety.

Superhydrophobic SERS substrates based on silver dendrite-decorated filter paper for trace detection of nitenpyram

In the present work, highly sensitive Raman detection of nitenpyram using superhydrophobic filter paper as substrates is introduced. The process is simple, and efficient. By sequentially coating silver dendrites and Octyltrimethoxysilane (OTMOS) on filter paper, we produced highly active surface-enhanced Raman scattering (SERS) substrates which show advancing and receding water contact angles of θ_A/θ_R = 159°/156°. Nitenpyram, a type of pesticides popularly used in agriculture, can be easily detected with the detection limit as low as 1 nM using the superhydrophobic filter paper as SERS substrates, which validates their use in Raman applications.