Determination of pesticides in sugarcane juice employing microextraction by packed sorbent followed by gas chromatography and mass spectrometry

Simple and selective extraction of quercetin with microextraction in packed syringe method using modified glass powder by a molecularly imprinted polymer followed by spectrophotometric determination

A new sample preparation method based on microextraction in packed syringe was developed for preconcentration of quercetin prior to its spectrophotometric determination. Molecularly imprinted polymers as packing material was used for higher extraction efficiency. First, glass powder as support material because of low cost and available substrate was modified, and then molecularly imprinted polymers were synthesized by the sol-gel method using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as cross-linker agent. The combination of a molecularly imprinted polymers and microextraction in packed syringe increased the selectivity and sensitivity. The surface morphology and functionality of the prepared molecularly imprinted polymers was characterized using Fourier-transform infrared spectroscopy, Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis. Different influencing parameters on extraction efficiency such as effect of the number of sample sorption/desorption cycles, type and volume of desorption solvent, pH of the sample solution, and molecularly imprinted polymers amounts were optimized. Under the optimum condition, the proposed method displayed a linear range from 0.01 to 5 µg mL-1 and limit of detection 3.68 ng mL-1 . Relative standard deviation for three replicate determination of 1 µg mL-1 quercetin was 2.1 %. The proposed method was applied successfully for the selective extraction of quercetin from tea and coffee samples.

Recent trends in pesticides in crops: A critical review of the duality of risks-benefits and the Brazilian legislation issue

Due to the increasing population worldwide, in recent years, an exponential increase in agricultural practices has occurred in order to attend to the growing demand for food. Unfortunately, this increase is not associated with the supply of foodstuffs free of environmental pollutants. In Brazil, agriculture is one of the most important economic pillars, making the country one of the largest consumers of pesticides around the world. The intense use of pesticides, mainly glyphosate, 2,4-D, and atrazine, constitutes an essential factor in the viability of this great agricultural productivity. Sugarcane, corn, soybean, and citrus crops consume around 66% of the total pesticides worldwide, representing 76% of the planted area. Pesticide residues have been frequently detected in food and the environment, becoming a significant concern for human health. Monitoring programs for pesticide use are essential to reduce the potential negative impacts on the environment and improve the overall efficiency and sustainability of their use. However, in Brazil, the approval status of pesticide-active ingredients is very discrepant compared to other agricultural countries. Moreover, the duality of benefits and risks of pesticide application creates an economic and toxicological conflict. In this paper, we have critically reviewed the duality of risks-benefits of the use of pesticides in agriculture and the current Brazilian legislation issues. We have also compared this flawed legislation with other countries with high economic potential. Due to the negative environmental impacts on soil and water by the high levels of pesticides, remediation techniques, sustainable agriculture, and the development of new technologies can be considered some viable alternatives to reduce the levels in these compartments. Besides, this paper includes some recommendations that can be included in the coming years.

Determination of selected herbicides in sugarcane-derived foods by graphene-oxide based disposable pipette extraction followed by liquid chromatography-tandem mass spectrometry

Sugarcane is widely cultivated in Brazil. Although there are Maximum Residue Limits of pesticides determined for this plant, there is no legislation covering alimentary products from sugarcane. In this study, Disposable Pipette Tip Extraction (DPX) technique was evaluated as a sample preparation technique for simultaneous determination of eleven herbicides followed by LC-MS/MS analysis in three sugarcane-derived food matrices: juice, candy, and syrup. First, graphene oxide anchored to silica functionalized with octadecyl silane and endcapped was synthesized, which was evaluated as a sorbent in DPX. Then, after evaluating the parameters involved in DPX extraction, the method was validated following the ICH guide. As a result, the method showed acceptable linearity (r ≥ 0.99), limits of quantification (1.0 - 5.0 ng mL^-1 for juice and 5.0 - 25.0 ng g ^- 1 for candy and syrup, varying according to the pesticide), precision, and accuracy within the limits of the literature, and recoveries ranging from 48 - 69% (juice), 34 - 89% (candy), and 28 - 76% (syrup). Finally, the developed method was successfully applied in actual samples of the three studied matrices.

Multidimensional capillary liquid chromatography-tandem mass spectrometry for the determination of multiclass pesticides in "sugarcane spirits" (cachaças)

Cachaça or "sugarcane spirit" is a Brazilian beverage considered the third most consumed beverage worldwide. Sugarcane, its raw material, is one of the main crops developed in the country, placing Brazil as the largest producer of this commodity on a global scale. Considering the growth in sugarcane production, many farmers use pesticides in their crops. However, excess pesticides can be accumulated in products derived from sugarcane, creating an environmental and public health concern. In this context, the development of analytical methods capable of identifying residues of pesticides in cachaças and other sugarcane-derived products is essential to ensure the beverage's quality. This work presents a method to quantify multiclass pesticides in Brazilian sugarcane spirits (cachaças) through an automated multidimensional system. The first dimension consists of an extraction column packed with a graphene-silica phase, followed by a capillary liquid chromatography-tandem mass spectrometry system as the second dimension. The method was optimized by an experimental design, in which the influence of three variables was evaluated on the extraction process: percentage of acetonitrile, loading flow, and loading time. Afterward, twenty-two cachaças were analyzed to ascertain the applicability of the proposed method. The analyses reported five samples containing clomazone (a type of herbicide widely used in sugarcane production). The method showed good linearity under optimized conditions, with correlation coefficients greater than 0.981, and limits of detection and quantification of 5 μg L^-1 and 10 μg L^-1, respectively. The herein discussed results suggest that the proposed method could be a practical option for identifying pesticides in beverages. Graphical Abstract.

Current trends on microextraction by packed sorbent – fundamentals, application fields, innovative improvements and future applications

MEPS, the acronym of microextraction by packed sorbent, is a simple, fast and user- and environmentally-friendly miniaturization of the popular solid-phase extraction technique (SPE).

Dissipation, occurrence and risk assessment of a phenylurea herbicide tebuthiuron in sugarcane and aquatic ecosystems in South China

In this study, a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method coupled with UPLC-QqQ-MS/MS analysis was developed to detect tebuthiuron in sugarcane fields and the surrounding aquatic ecosystems. Methodological validation showed the method developed was of favorable sensitivity, reproducibility and accuracy. For assessment of its dietary and ecological risks, dissipation and occurrence of tebuthiuron in situ were further investigated through a supervised field trial and an aquatic environment monitoring carried out in six dominant sugarcane production regions in South China. After application at the range of recommended dose, tebuthiuron dominantly distributed in soil, and then dissipated in accordance with the first-order rate model with the half-lives of 12.2-21.5 d. At pre-harvest intervals (PHI), occurrence of tebuthiuron was found to be 0.718-1.366 mg/kg and 0.016-0.034 mg/kg, in sugarcane and soil, respectively. The supervised trials median residue (STMR) of tebuthiuron in sugarcane was thus 0.024 mg/kg and the dietary Risk Quotient (RQ_d) was accordingly calculated as 2.34 × 10^-4, indicating safety on long-term consumption of sugarcane with tebuthiuron residues. Yet high risks of tebuthiuron towards soil ecosystems was noticed as it possessed maximum ecological Risk Quotient (RQ_e) at 1.97 to earthworms. In sugarcane field-surrounding aquatic environment, distribution of tebuthiuron was found to range from 0.007 mg/L to 0.022 mg/L, leading to high risk towards the aquatic ecosystem due to the maximum RQ_e at 440 to algae, irrespective of its low risks to invertebrate and fish. Taken together, our approach serve as an effective tool for monitoring residual tebuthiuron environmentally and also advance in-depth understanding of dietary and ecological risks posed by the phenylurea herbicide.