Evaluating BTEX in vehicle exhaust gas: A fast and efficient approach using SPME and GC-BID.

Benzene, toluene, ethylbenzene, and the xylene isomers (m, p, and o-xylene) (BTEX) are known for their harmful effects on human health and have been extensively studied across various environmental matrices. However, quantifying BTEX in exhaust gases poses challenges due to the complexity of the matrices. In this study, we investigated a method development strategy involving solid-phase microextraction (SPME) and gas chromatography coupled with a dielectric barrier discharge ionization Detector (BID) for quantifying BTEX emitted from internal combustion engines operating at idle. Sampling was conducted using 1.0 L Tedlar bags, followed by withdrawal of aliquots and dilution with atmospheric air using a novel device (graduated vial) designed for gaseous samples. The SPME-GC-BID method was developed and validated for the conditions: BTEX extraction in CAR/PDMS 75 µm fiber at a contact time of 5.0 min at a temperature of 27 °C, followed by GC-BID analysis. Method validation to ensure the reliability of quantitative results used the merit figures e.g., limits of detection (LOD) and quantification (LOQ), precision, and accuracy (recovery). LOD varied from 0.194 to 0.340 mg m-3, LOQ varied from 0.587 to 1.03 mg m-3, precision ranged from 1.47 to 7.14 %, and recovery varied from 82.34 to 109.5 %. BTEX concentration in vehicle exhaust varied from 3.40 to 16.4 mg m-3. The results showed, concerning the figures of merit analyzed, that the SPME-GC-BID method provides good sensibility, precision, and accuracy for evaluating the presence of BTEX in the exhaust of internal combustion engines, contributing to the understanding of health risks associated with vehicle emissions.

Statistical evaluation of analytical curves for quantification of pesticides in bananas.

The aim of this paper is to statistically validate the analytical curves of a chromatography method to identify and quantify azoxystrobin, difenoconazole and propiconazole residues in banana pulp, using QuEChERS and GC-SQ/MS. A matrix-matched calibration was used and analytical curves were estimated by weighted least squares regression (WLS), confirming heteroscedasticity for all compounds. Statistical tests were performed to confirm the quality adjustment of the proposed linear model. The correlation coefficient for azoxystrobin, difenoconazole and propiconazole were, respectively, 0.9985, 0.9966 and 0.9997 (concentration range: 0.05 and 2.0 mg kg-1). The limits of detection and quantification were, respectively, between 0.007 and 0.066 mg kg-1, and between 0.022 and 0.199 mg kg-1, below the maximum limits stipulated by Brazilian, American, and European legislation. Only difenoconazole had an insignificant matrix effect (6.8%). Thus, the weighted least squares method is shown to be a safe linear regression model, providing greater reliability of the results.

A socio-environmental perspective on pesticide use and food production.

Pesticides are part of a large group of organic compounds with different physicochemical characteristics, designed to control and prevent pests in various crops and plantations, improving productivity. This works provides a perspective on pesticide use in current agriculture with the aim of identifying the influence of pesticides on food production and their impact on the environment. Therefore, it is necessary to highlight the importance of determining pesticide residues in food, aiming to ensure food safety, since these compounds can represent risks to human health and the environment. The effects of pesticides on humans range from headaches, nausea and skin and eye irritation to chronic problems such as cancer and neurological disorders, and extend to other non-target organisms such as birds, fish and bees, contaminating water, soil, and plants, as opposed to the benefits of increased production, consequently other measures for pesticide consumption need to be evaluate to ensure human health, food safety and environmental protection. It is important to note that chromatographic techniques and mass spectrometry assist in the determination of pesticide residues and evaluate the quality of the food that reaches the consumer, and together with the Maximum Residue Limits (MRLs), established by the legislation of each country, these instrumentation act to control the exposure of population to pesticides. Although the MRL is used as a parameter for food quality, the global differences in pesticide legislation do not guarantee the consumer safety. In this sense, a brief analysis of MRL inefficiency is also present in this paper.

Evaluating the presence of pesticides in bananas: An integrative review.

INTRODUCTION: Pesticides are organic compounds widely used in modern agriculture, being relevant for helping plantations and increasing food production. The banana, a fruit with oriental origin, stands out for being widely produced in tropical and subtropical regions which, like other matrices, is susceptible to pest action. This review aims to evaluate the presence of pesticides in bananas according to Brazilian, European and Codex legislation. METHODS: Four databases, ScienceDirect, SciELO, PubMed and Springer, were used to find relevant articles in the literature addressing methods for the determination of pesticide residues in bananas using the terms "banana", "chromatography", "pesticides" and "determination". The search stages included reading abstracts and titles, reading the full text, extracting data and analyzing data from eligible articles. The search was restricted to original research articles published in English from 2008 to 2018. RESULTS: 404 articles were found from the initial research, with only 15 studies being considered eligible for this review. Mass spectrometry is the most widely used detection technique. 5 articles were seen to use a multiresidue method to analyze only bananas (pulp), and from these, only 2 studies used methods to analyze the pulp and peel. The articles analyzed 172 samples, with 59.3% of these being conducted in Europe, 32.5% being conducted in Asia and only 8.1% in South America. A total of 79.1%, 32.4% and 42.6% of samples were unsatisfactory according to the Brazilian, European and Codex legislation, respectively, with these samples being contaminated with pesticide residues. CONCLUSION: This review presents the scarcity of articles aimed at identifying pesticide residues in bananas and the urgency of checking the quality of the fruit that reaches the population. The MRLs allowed by different legislations have clear divergences that do not ensure the lowest concentration values that guarantee consumer safety.