Analysis of glyphosate and aminomethylphosphonic acid in leaves from Coffea arabica using high performance liquid chromatography with quadrupole mass spectrometry detection

Synthesis and application of a dual-functional fluorescent probe for sequential recognition of Zn2+and glyphosate

A novel fluorescent probe QL was designed and synthesized based on Schiff base by 2-hydrazinobenzothiazole to sequentially recognize Zn2+ and glyphosate. The probe QL was capable to detect Zn2+ in DMSO solution via fluorescence enhancement, and exhibited good selectivity and anti-interference ability. The combination mode was 1:2 between probe QL and Zn2+ according to the method of job's plot, and the detection limit of probe QL for Zn2+ was found to be 4.51 × 10-8 M, which exhibited excellent sensitivity. Furthermore, the system QL-Zn2+ could detect glyphosate by causing fluorescence quenching response and with a color change from yellow to colorless for naked-eye detection. The detection limit for glyphosate was found to be 4.93 × 10-8 M, which was far below the Standards for Drinking Water Quality (GB5749-2006) acceptable limits (0.7 μg/mL for glyphosate). Notably, the probe QL and its complex QL-Zn2+ have been successfully applied to detect Zn2+ and glyphosate in water, respectively.

GLYPHOSATE IMPACT on human health and the environment: Sustainable alternatives to replace it in Mexico

Glyphosate is a broad-spectrum, non-selective herbicide used to control weeds and protect agricultural crops, and it is classified as potentially carcinogenic by the International Agency for Research on Cancer. In Mexico, the use of pesticides is a common practice, including glyphosate. However, on December 31st, 2020, the Mexican government decreed the prohibition of this herbicide as of January 2024. In this review, we investigate the association between glyphosate and cancer risk and found that most of the studies focused using animals showing negative effects such as genotoxicity, cytotoxicity and neurotoxicity, some studies used cancer cell lines showing proliferative effects due to glyphosate exposure. To our knowledge, in Mexico, there are no scientific reports on the association of glyphosate with any type of cancer. In addition, we reviewed the toxicological effects of the herbicide glyphosate, and the specific case of the current situation of the use and environmental damage of this herbicide in Mexico. We found that few studies have been published on glyphosate, and that the largest number of publications are from the International Agency for Research on Cancer classification to date. Additionally, we provide data on glyphosate stimulation at low doses as a biostimulant in crops and analytical monitoring techniques for the detection of glyphosates in different matrices. Finally, we have tried to summarize the actions of the Mexican government to seek sustainable alternatives and replace the use of glyphosate, to obtain food free of this herbicide and take care of the health of the population and the environment.

Method of Glyphosate, AMPA, and Glufosinate Ammonium Determination in Beebread by Liquid Chromatography-Tandem Mass Spectrometry after Molecularly Imprinted Solid-Phase Extraction

The aim of this study was to develop a method for the determination of glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and glufosinate ammonium residues in beebread samples, which could then be used to assess bees' exposure to their residues. The complexity of beebread's matrix, combined with the specific properties of glyphosate itself, required careful selection and optimization of each analysis step. The use of molecularly imprinted solid-phase extraction (MIP-SPE) by AFFINIMIP glyphosate as an initial clean-up step significantly eliminated matrix components and ensured an efficient derivatization step. Colorless beebread extracts were derivatized by the addition of 9-fluorenylmethyl chloroformate (FMOC-Cl). After derivatization, in order to remove FMOC-OH and residual borate buffer, a solid-phase extraction (SPE) clean-up step using Oasis HLB was carried out. Instrumental analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The method was validated according to the SANTE/11312/2021 guideline at concentrations of 5, 10, and 100 µg/kg, and satisfactory recovery (trueness) values (76-111%) and precision (RSDr) ≤ 18% were obtained. The limit of quantification (LOQ) was 5 µg/kg for AMPA and glufosinate ammonium and 10 µg/kg for glyphosate. The method was positively verified by the international proficiency test. Analysis of beebread samples showed the method's usefulness in practice. The developed method could be a reliable tool for the assessment of beebread's contamination with residues of glyphosate, its metabolite AMPA, and glufosinate ammonium.

Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents

In this work, molecular imprinting was combined with direct fluorescence detection of the pesticide Glyphosate (GPS). Firstly, the solubility of highly polar GPS in organic solvents was improved by using lipophilic tetrabutylammonium (TBA⁺) and tetrahexylammonium (THA⁺) counterions. Secondly, to achieve fluorescence detection, a fluorescent crosslinker containing urea-binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2-3 nm fluorescent molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles using chloroform as porogen. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA⁺ counterion was found to be a more powerful phase transfer agent than TBA⁺ in a biphasic assay, enabling the direct fluorescence detection and quantification of GPS in water. A limit of detection of 1.45 µM and a linear range of 5-55 µM were obtained, which match well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 µM).

Determination of Aminophosphonate Herbicides in Glutamate Loaded Spice Mix by LC-IDMS and Method Extension to Other Food Matrices

The accumulation of organophosphorus type herbicides has been observed worldwide in the environment (i.e. soil, water), together with their appearance in foods of plant origin. This paper reports a new liquid chromatography–isotope dilution–tandem mass spectrometric method (LC-IDMS) for the analysis of glufosinate (GLUF), glyphosate (GLY) and its main metabolite, aminomethylphosphonic acid (AMPA), in challenging food samples. Sample preparation is based on aqueous extraction with ethylenediaminetetraacetic acid solution, followed by solid-phase extraction (SPE) on mixed-mode cation exchange cartridges to remove matrix constituents before derivatization with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl). Derivatized samples were cleaned up on hydrophilic modified polymeric SPE cartridge. This two-step SPE supported sample preparation approach, and the LC-IDMS separation carried out in negative ionization mode resulted in fit-for-purpose recovery (81–118%) and precision (4–18%) in the validation of glutamate loaded spice mix, mushroom, maize and cherry samples. Amino acid content influencing FMOC derivatization efficiency was estimated with a HILIC-MS/MS setup. Multiple reaction monitoring (MRM) was assisted with high-resolution (QTOF) accurate mass data on the FMOC-derivatized GLUF, GLY and AMPA standards. The limit of quantification (LOQ) was 0.005 mg/kg for all the three analytes. The method was successfully applied on quality control samples (oat and arugula) with fit-for-purpose accuracy (99–120%) and on other nineteen real samples, where GLY and AMPA were detected in the range between 0.005 and 0.069 mg/kg.

Immobilization of bovine hemoglobin on Au nanoparticles/MoS2 nanosheets - Chitosan modified screen-printed electrode as chlorpyrifos biosensor

In this paper a quick and disposable electrochemical biosensor based on bovine hemoglobin (BHb) is proposed for the determination of chlorpyrifos (CP). The bioelectrode (denoted as AuNPs/MoS₂-CS/BHb/SPE) has been designed by immobilizing BHb on the screen printed electrode (SPE) surface modified by gold nanoparticles (AuNPs) and Molybdenum disulfide (MoS₂) nanosheets - chitosan (CS) mixture (MoS₂-CS). Field emission scanning electron microscopy (FESEM) and electrochemical characterization demonstrate the successful grafting of AuNPs/MoS₂-CS/BHb/SPE. Detailed electrochemical impedance spectroscopy (EIS) analysis and cyclic voltammetry (CV) tests show that the proposed bioelectrode exhibits decent electrochemical properties, such as well conductivity and large specific surface area. In-depth electrochemical analysis reveals the redox reaction occurring on the surface of the bioelectrode and the mechanism that CP binds with BHb forming the thin film to inhibit the peak current. The proposed biosensor exhibits sensitive and stable responses for electrochemical assay of CP ranging from 0.004 μM to 28.52 μM, with a limit of detection (LOD) as 5.6 nM. The electrochemical biosensor passes the repeatability, reproducibility, stability and anti-interference ability test experiments with good performance. The biosensor also shows its credibility for detecting CP in real vegetable samples (Cabbage and Leek) with recovery (%) ranging from 87% to 109%. The proposed biosensor is of great potential application values for detecting CP and the study is of great reference value for the research and development of biosensors for quantitative detection of organophosphate pesticides (OPs).

Magnetic Molecularly Imprinted Polymer for the Selective Enrichment of Glyphosate, Glufosinate, and Aminomethylphosphonic Acid Prior to High-Performance Liquid Chromatography

A novel mixed iron hydroxide molecularly imprinted polymer (MIH-MIP) was synthesized via polymerization using mixed-valence iron hydroxide as a magnetic supporter, glyphosate as a template, acrylamide as a functional monomer, and ethylene glycol dimethacrylate as a cross-linker. The resulting material was characterized and applied as a sorbent for the selective enrichment of glyphosate, aminomethylphosphonic acid, and glufosinate by magnetic solid-phase extraction (MSPE) prior to high-performance liquid chromatography. MIH-MIP possessed a high adsorption capacity in the range of 2.31-5.40 mg g^-1 with good imprinting factors ranging from 1.52 to 7.59. The Langmuir model proved that the recognition sites were distributed as a monolayer on the surface of MIH-MIP. Scatchard analysis showed two types of binding sites on MIH-MIP. The kinetic characteristics of MIH-MIP suggested that the binding process of all analytes fit well with the pseudosecond-order model. The developed methodology provides good linearity in the range of 72.0-2000.0 μg L^-1. Low detection limits of 21.0-22.5 μg L^-1 and enrichment factors of up to 18 were achieved. The precision in terms of relative standard deviations of the intra- and interday experiments was better than 7 and 9%, respectively. The applicability of the developed MSPE facilitates the accurate and efficient determination of water, soil, and vegetable samples with satisfactory recoveries in the range of 86-118%. The results confirmed the suitability of the MIH-MIP sorbent for selective extraction and quantification of glyphosate, aminomethylphosphonic acid, and glufosinate.

A method to assess glyphosate, glufosinate and aminomethylphosphonic acid in soil and earthworms

A new sensitive and selective analytical methodology to quantify glyphosate (GLY), aminomethylphosphonic acid (AMPA), and glufosinate (GLU) in both soil and earthworms (Allolobophora chlorotica) was developed. The extraction and purification methods were optimized. The samples were extracted with various aqueous solutions (HNO3, H2O, KOH and borate buffer) and derivatized with 9-Fluorenylmethyl chloroformate (FMOCCl). To optimize the extraction step, a method to remove the excess FMOCCl was applied based on liquid-liquid extraction with diethyl ether. The purification of derivatized extracts was carried out using XLB solid phase extraction (SPE) cartridges before internal standard quantification by liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). The elution step was optimized to obtain the best recoveries possible, which was with acidic methanol (1% formic acid) (67% for GLY, 70% for GLU and 65% for AMPA). The extraction and purification method followed by analysis of the two herbicides and AMPA in soils using LC/MS/MS determined limit of quantification (LOQ) values of 0.030 μg g - 1 for GLY, 0.025 μg g - 1 for AMPA and 0.020 µg g - 1 for GLU . For earthworms, LOQ were 0.23 μg g - 1 for GLY, 0.20 μg g - 1 for AMPA and 0.12 μg g - 1 for GLU. . The developed method was applied to determine these compounds in natural soils and earthworms.

The carbon stable isotope compositions of glyphosate and aminomethylphosphonic acid (AMPA): Improved analytical sensitivity and first application to environmental water matrices

RATIONALE

The presence of glyphosate and its degradation product aminomethylphosphonic acid (AMPA) in the environment has adverse effects on environmental quality, raising the need to better constrain their fates, in particular the processes that control their production and degradation. Our aim was to improve the sensitivity of their δ¹³ C analysis and demonstrate the feasibility of measuring them in natural surface water.

METHODS

The δ¹³ C values of dissolved glyphosate and AMPA were determined using isotope ratio mass spectrometry (IRMS) (Delta V Plus instrument) coupled to a high-performance liquid chromatography (HPLC) unit, where glyphosate and AMPA were separated on a Hypercarb column.

RESULTS

We demonstrated an improved sensitivity of the δ¹³ C analysis for glyphosate and AMPA by LC/IRMS compared with previous studies. For waters from the carbonate and silicate hydrofacies, while no pretreatment was required for the isotope analysis of glyphosate, removal by H₃ PO₄ acidification of dissolved inorganic carbon, that co-elutes with AMPA, was required prior to its analysis. We successfully tested a freeze-drying pre-concentration method showing no associated isotope fractionation up to concentration factors of 500 and 50 for glyphosate and AMPA, respectively.

CONCLUSIONS

We demonstrated, for the first time, the feasibility of measuring the δ¹³ C values of glyphosate and AMPA in natural surface waters with contrasted hydrofacies (calcium carbonate and silicate types). This opens new fields in pesticide research, especially on the characterization of processes that control their degradation and the production of their secondary byproducts.

Field-amplified sample injection and sweeping micellar electrokinetic chromatography in analysis of glyphosate and aminomethylphosphonic acid in wheat

Glyphosate, a widely used herbicide, has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer (IARC). In the present study a method based on Field-Amplified Sample Injection and Sweeping Micellar Electrokinetic Chromatography (FASI sweep-MEKC) has been developed and validated for determination of glyphosate and its microbial metabolite aminomethylphosphonic acid (AMPA) in wheat flour. The method involved a preliminary solid phase extraction for cleanup of the aqueous extracts from wheat flour, based sequentially on C18 and strong anion exchange cartridges, followed by derivatization using 9-fluorenylmethylchloroformate. Optimization of sample cleanup and derivatization procedure was carried out by a HPLC-UV method, whereas FASI sweep-MEKC was applied for achieving the sensitivity necessary for analysis of real samples. To this regard, optimum conditions involved the use of an extended path fused-silica capillary (80 cm total length, 50 μm, i.d.) filled with a high concentration buffer (sodium phosphate 100 mM, pH 2.2). Electrokinetic sampling was carried out at -10 kV with injection time of 700 s and the separation of the loaded analytes was performed under MEKC conditions using sodium phosphate buffer 50 mM at pH 2.2, supplemented with sodium dodecyl sulfate, 100 mM. The method was validated for linearity, precision, accuracy and sensitivity, showing that using conventional UV detection (210 nm) the achieved limit of quantitation (LOQ) values for both the analytes were widely lower than those set by Authorities. In particular, LOQ for glyphosate and AMPA were found to be 5 and 2.5 ng/mL, respectively, corresponding to 0.1 and 0.05 mg/kg, in wheat flour. The method, applied to commercially available real samples (wheat flour from different manufacturers) and to an experimental sample obtained by cv. Svevo wheat, can be considered as a convenient alternative to the existing approaches in analysis of complex matrices.

Widespread occurrence of glyphosate in urine from pet dogs and cats in New York State, USA

Glyphosate is one of the most widely used herbicides in the United States, which has led to its ubiquitous occurrence in food and water and regular detection in human urine at concentrations of 1-10 μg/L. Data pertaining to health risks arising from the ingestion of glyphosate are limited and are the subject of much debate, which demands the need for more exposure information for this herbicide. Very little is known about glyphosate exposure in pets. In this study, we determined concentrations of glyphosate (Glyp) and its derivatives, methyl glyphosate (Me-Glyp) and aminomethylphosphonic acid (AMPA), in urine collected from 30 dogs and 30 cats from New York State, USA. Glyp was the most predominant compound found in pet urine followed by AMPA and Me-Glyp. The mean urinary concentration of ∑Glyp (sum of Glyp + Me-Glyp + AMPA) in cats (mean: 33.8 ± 46.7 ng/mL) was 2-fold higher than that in dogs (mean: 16.8 ± 24.4 ng/mL). Cumulative daily intakes (CDI) of Glyp in dogs and cats estimated from the urinary concentrations were, on average, 0.57 and 1.37 μg/kg bw/d, respectively. The exposure doses were two to four orders of magnitude below the current acceptable daily intake (ADI) suggested by several international health organizations for humans.

A method for determining glyphosate and its metabolite aminomethyl phosphonic acid by gas chromatography-flame photometric detection

As a globally popular herbicide, glyphosate (GLY) and its metabolite aminomethylphosphonic acid (AMPA) pose potential hazards to the ecological environment. In this study, a sensitive and reliable method for detecting GLY and AMPA was utilized to facilitate exposure risk assessment of the analytes in environmental systems such as water and soil. GLY and AMPA were extracted from the sample using a solid-phase extraction (SPE) procedure, derivatized by heptafluorobutyric anhydride and heptafluorobutanol, and detected by gas chromatography-flame photometric detection (GC-FPD). The linearities of GLY and AMPA in the range of 10-1000 ng/mL were good (r=0.9998, r=0.9991), and the limits of quantitation (LOQ) for GLY and AMPA were 0.37 and 0.81 ng/mL, respectively. The method has been successfully applied for detecting GLY and AMPA in water, soil and monitoring the degradation of GLY under different environmental conditions. Simulated migration characteristics of GLY and AMPA in soil were investigated for evaluating the potential hazards of GLY and AMPA to the ecological environment.

Determination of glyphosate residues in Egyptian soil samples

A sensitive linker-assisted enzyme-linked immunosorbent assay (L'ELISA) was developed for the analysis of glyphosate in Egyptian soil samples. Polyclonal glyphosate antibodies were produced from rabbits immunized with glyphosate protein conjugate. The conjugate was prepared by activating the carboxylic groups of proteins; thyroglobulin or bovine serum albumin with 1-ethyl-3- (3-diaminopropyl) carbodiimide hydrochloride and N-hydroxysulfosuccinimide followed by directly coupled to the amino group of glyphosate. The L'ELISA used succinic anhydride to derivatize glyphosate, which mimics the epitopic attachment of glyphosate to thyroglobulin. L'ELISA recognized the derivatized glyphosate with a limit of detection (LOD) of 0.8 ng g-1 and sensitivity (IC50 value) of 0.018 μg g-1. The recovery values of the spiked soil samples with different concentrations of glyphosate were in the range of 87.4-97.2%. Good correlation was achieved between L'ELISA and conventional high-pressure liquid chromatography (HPLC) with fluorescence detection. This study demonstrated the utility and convenience of the sensitive, simple, practical and cost-effective L'ELISA method for glyphosate analysis in soil samples. Also, it is ideal for rapid screening of a large number of environmental samples.

Direct determination of glyphosate and aminomethyl phosphonic acid in honeybees

A straightforward LC-ESI-MS/MS method was developed and validated for the detection and quantitation of the herbicide glyphosate (GLY) and its metabolite aminomethyl phosphonic acid (AMPA) in honeybees. The method was validated, fulfilling the SANTE 11945/2015 guideline criteria, demonstrating acceptable mean recoveries at LOQ and 10×LOQ varying from 75-87% for both compounds. LOQ was determined at 0.2 and 0.5 μg/g bee body weight (bw) for GLY and AMPA respectively. Analysis of 14 honeybee samples displayed only one positive sample, containing GLY marginally above LOQ and traces of AMPA.

A Highly Selective and Sensitive Fluorescence Detection Method of Glyphosate Based on an Immune Reaction Strategy of Carbon Dot Labeled Antibody and Antigen Magnetic Beads

A sensitive fluorescence detection method for glyphosate (GLY) was established based on immune reaction. First, carbon dot labeled antibodies (lgG-CDs) which were able to specifically identify glyphosate were prepared with the environmentally friendly carbon dots (CDs) and glyphosate antibody (lgG). lgG-CDs could be used to in situ visualize the distribution of glyphosate in plant tissues. In order to eliminate the effects of excess lgG-CDs on the determination of GLY, antigen magnetic beads Fe3O4-GLY based on magnetic nanoparticles Fe3O4 and glyphosate were constructed and utilized to couple with the excess lgG-CDs. After magnetic separation to remove antigen magnetic beads, there was a linear relationship between the fluorescence intensity of lgG-CDs and the logarithmic concentration of glyphosate in the range of 0.01-80 μg/mL with a detection limit of 8 ng/mL. The method was used for the detection of glyphosate in Pearl River water, tea, and soil samples with satisfactory recovery ratio between 87.4% and 103.7%.

Analysis of glyphosate and aminomethylphosphonic acid in water, plant materials and soil

There is a need for simple, fast, efficient and sensitive methods of analysis for glyphosate and its degradate aminomethylphosphonic acid (AMPA) in diverse matrices such as water, plant materials and soil to facilitate environmental research needed to address the continuing concerns related to increasing glyphosate use. A variety of water-based solutions have been used to extract the chemicals from different matrices. Many methods require extensive sample preparation, including derivatization and clean-up, prior to analysis by a variety of detection techniques. This review summarizes methods used during the past 15 years for analysis of glyphosate and AMPA in water, plant materials and soil. The simplest methods use aqueous extraction of glyphosate and AMPA from plant materials and soil, no derivatization, solid-phase extraction (SPE) columns for clean-up, guard columns for separation and confirmation of the analytes by mass spectrometry and quantitation using isotope-labeled internal standards. They have levels of detection (LODs) below the regulatory limits in North America. These methods are discussed in more detail in the review.