Determination of pesticides of different chemical classes in drinking water of the state of Santa Catarina (Brazil) using solid-phase microextraction coupled to chromatographic determinations

Thin-film solid-phase microextraction of pesticides from cereal samples using electrospun polyvinyl alcohol/modified chitosan/porous organic framework nanofibers

In this study, a coating of electrospun polyvinyl alcohol/modified chitosan/hydroxy-containing porous organic framework (PVA/MCS/HC-POF) was fabricated and applied as a novel sorbent for thin-film solid-phase microextraction of pesticides from cereal samples, followed by HPLC-UV. The successful fabrication of PVA/MCS/HC-POF was confirmed through characterization tests. The functional group of MCS and a large number of hydroxyl groups on the HC-POF structure contributed to the co-extraction of pesticides. Under the optimum conditions, the calibration plots were linear within the range of 5.0-800 ng mL-1 (r2 ≥ 0.978), and the limits of detection were obtained below 4.0 ng mL-1. The method's precision was investigated through intra-day, inter-day, and film-to-film RSD (%) measurements, all of which were less than 6.5 %, 8.2 %, and 10.0 %, respectively. Furthermore, satisfactory recoveries ranging from 63.3 % to 79.0 % were obtained. Accordingly, the proposed method can be considered a suitable alternative for measuring trace amounts of pesticides in cereal samples.

Development of In-Needle SPME Devices for Microextraction Applied to the Quantification of Pesticides in Agricultural Water

The chemical industry explosion in the 20th century has led to increased environmental pollution, affecting fauna, flora, and waterways. These substances alter water's taste, color, and smell, making it unfit for consumption or toxic. Agricultural water networks face threats from pollution before and after treatment. Some chemical contaminants, like pesticides, are embedded in natural biogeochemical cycles. In this study, we developed a simple and low-cost procedure for the fabrication of needles coated with polydimethylsiloxane (PDMS) as an efficient sorbent for the microextraction of organic pollutant traces from water. The prepared needles were used as an alternative for commercial solid-phase micro-extraction (SPME) devices in analytical chemistry. The PDMS polymeric phase was characterized by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and scanning electron microscopy (SEM). The PDMS-coated needles were used for extraction of thirteen pesticides by direct-immersion solid-phase microextraction (DI-SPME) from contaminated waters, followed by determination with gas chromatography-mass spectrometry (GC-MS). The developed analytical method showed limits of detection (LODs) between 0.3 and 2.5 ng mL-1 and RSDs in the range of 0.8-12.2%. The homemade needles were applied for the extraction of pesticides in surface and ground aqueous samples collected from an agricultural area. Several target pesticides were identified and quantified in the investigated water samples.

A novel honeycomb-like 3D-printed device for rotating-disk sorptive extraction of organochlorine and organophosphorus pesticides from environmental water samples

In this study, 3D-printing based on fused-deposition modeling (FDM) was employed as simple and cost-effective strategy to fabricate a novel format of rotating-disk sorptive devices. As proof-of-concept, twenty organochlorine and organophosphorus pesticides were determined in water samples through rotating-disk sorptive extraction (RDSE) using honeycomb-like 3D-printed disks followed by gas chromatography coupled to mass spectrometry (GC-MS). The devices that exhibited the best performance were comprised of polyamide + 15 % carbon fiber (PA + 15 % C) with the morphology being evaluated through X-ray microtomography. The optimized extraction conditions consisted of 120 min of extraction using 20 mL of sample at stirring speed of 1100 rpm. Additionally, liquid desorption using 800 µL of acetonitrile for 25 min at stirring speed of 1100 rpm provided the best response. Importantly, the methodology also exhibited high throughput since an extraction/desorption platform that permitted up to fifteen simultaneous extractions was employed. The method was validated, providing coefficients of determination higher than 0.9706 for all analytes; limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.15 to 3.03 μg L-1 and from 0.5 to 10.0 μg L-1, respectively. Intraday precision ranged from 4.01 to 18.73 %, and interday precision varied from 4.83 to 20.00 %. Accuracy was examined through relative recoveries and ranged from 73.29 to 121.51 %. This method was successfully applied to analyze nine groundwater samples from monitoring wells of gas stations in São Paulo. Moreover, the greenness was assessed through AGREEprep metrics, and an overall score of 0.69 was obtained indicating that the method proposed can be considered sustainable.

Neurotoxicity of Pyrethroids in neurodegenerative diseases: From animals' models to humans' studies

Neurodegenerative diseases are associated with diverse symptoms, both motor and mental. Genetic and environmental factors can trigger neurodegenerative diseases. Chemicals as pesticides are constantly used in agriculture and also domestically. In this regard, pyrethroids (PY), are a class of insecticides in which its main mechanism of action is through disruption of voltage-dependent sodium channels function in insects. However, in mammals, they can also induce oxidative stress and enzyme dysfunction. This review investigates the association between PY and neurodegenerative diseases as Alzheimer's, Huntington's, Parkinson's, Amyotrophic Lateral Sclerosis, and Autism in animal models and humans. Published works using specific and non-specific models for these diseases were selected. We showed a tendency toward the development and/or aggravating of these neurodegenerative diseases following exposure to PYs. In animal models, the biochemical mechanisms of the diseases and their interaction with the insecticides are more deeply investigated. Nonetheless, only a few studies considered the specific model for each type of disease to analyze the impacts of the exposure. The choice of a specific model during the research is an important step and our review highlights the knowledge gaps of PYs effects using these models reinforcing the importance of them during the design of the experiments.

The fungicide tebuconazole modulates the sodium current of human NaV1.5 channels expressed in HEK293 cells

The fungicide Tebuconazole is a widely used pesticide in agriculture and may cause cardiotoxicity. In our present investigation the effect of Tebuconazole on the sodium current (INa) of human cardiac sodium channels (NaV1.5) was studied using a heterologous expression system and whole-cell patch-clamp techniques. Tebuconazole reduced the amplitude of the peak INa in a concentration- and voltage-dependent manner. At the holding potential of -120 mV the IC50 was estimated at 204.1 ± 34.3 μM, while at -80 mV the IC50 was 0.3 ± 0.1 μM. The effect of the fungicide is more pronounced at more depolarized potentials, indicating a state-dependent interaction. Tebuconazole caused a negative shift in the half-maximal inactivation voltage and delayed recovery from fast inactivation of INa. Also, it enhanced closed-state inactivation, exhibited use-dependent block in a voltage-dependent manner. Furthermore, Tebuconazole reduced the increase in late sodium current induced by the pyrethroid insecticide β-Cyfluthrin. These results suggest that Tebuconazole can interact with NaV1.5 channels and modulate INa. The observed effects may lead to decreased cardiac excitability through reduced INa availability, which could be a new mechanism of cardiotoxicity to be attributed to the fungicide.

New Trend in the Extraction of Pesticides from the Environmental and Food Samples Applying Microextraction Based Green Chemistry Scenario: A Review

This review focused on the green microextraction methods used for the extraction of pesticides from the environmental and food samples. Microextraction techniques have been explored and applied in various fields of analytical chemistry since its beginning, as evinced by the numerous reviews published. The success of any technique in science and technology is measured by the simplicity, environmentally friendly, and its applications; and the microextraction technique is highly successive. Deliberations were attentive to studies where efforts have been made to validate the methods through the inter-laboratory comparison study to assess the analytical performance of microextraction techniques against conventional methods. Succinctly, developed microextraction methods are shown to impart significant benefits over conventional techniques. Provided that the analytical community continues to put forward attention and resources into the growth and validation of the microextraction technique, a promising future for microextraction is forecasted.