SOUTHERN JOURNAL OF SCIENCES

Introduction: The detection of methanol in alcoholic beverages represents a critical public health issue, particularly in light of the recent outbreak of poisonings in Brazil, which registered 58 confirmed cases and 15 deaths through October 2025. Methanol's toxicity, with an estimated lethal dose ranging from 0.5 to 1.5 g/kg, requires reliable analytical methods for health surveillance. Brazilian legislation establishes a maximum limit of 20 mg/100 mL of anhydrous alcohol; however, the need for accessible screening methods in field settings remains an important challenge. Objective: To critically compare three analytical methods for methanol determination: classical qualitative methods (Lucas Test and dichromate/Schiff), Brazilian colorimetric method, and gas chromatography with flame ionization detector (GC-FID), evaluating their performance and applicability in resource-limited contexts. Methods: Theoretical-comparative approach through critical analysis of specialized literature and normative technical documentation. Methods were evaluated according to: operational principle, sensitivity (LOD/LOQ), selectivity, operational complexity, analysis time, and practical applicability. Results: The Lucas Test is not applicable for methanol detection. Colorimetric methods showed moderate sensitivity (LOD ~20-160 mg/100 mL), a 10-30-minute execution time, low operational complexity, and excellent portability. The Brazilian method presented chemical equivalence with international standards, differing only in the type of reading performed. GC-FID has shown superior sensitivity (LOD ≤ 1 mg/100 mL) and high specificity, but it requires extended time (~45-60 minutes), complex laboratory infrastructure, and specialized operators. Sugars interfere with colorimetric methods. Conclusions: The methods are complementary within a hierarchical system. Colorimetric methods enable rapid field screening, while GC-FID serves as the confirmatory method for forensic analyses. We recommend implementing integrated protocols that combine in situ colorimetric screening with GC-FID confirmation in accredited laboratories for effective health surveillance.

Background: Human echinococcosis is a zoonotic disease caused by Echinococcus granulosus, the etiological agent of cystic echinococcosis (CE). Aim: This study aims to determine the epidemiological prevalence of Echinococcus granulosus in patients with hydatid cysts and evaluate serum TNF-α levels associated with echinococcosis, as well as the correlation between these levels and disease progression. Methods: Radiological examinations were performed to diagnose Echinococcus granulosus by identifying echinococcal cysts. The study included patients of all ages and both sexes from Al-Sader Medical City, Al-Hakeem General Hospital, Al-Haidarya General Hospital, and Al-Hayat Hospital. The study period was from October 2023 to the end of January 2024. Results: The mean TNF-α level in patients was 163.27 pg/ml, significantly higher than the mean level of 38.58 pg/ml in controls (p-value < 0.001). Conclusion: The prevalence of hydatid disease in Al-Najaf Al-Ashraf was found to be 33%. TNF-α levels are notably higher in patients with Echinococcus granulosus who are under 40 years of age compared to those over 40 years of age.

Demand for diversified biodiesel feedstocks is high and increasing, but few are viable for large-scale production, and many of those selected compete with other sectors of the chemical industry. To improve energy and environmental sustainability, fatty acids from waste oils that are improperly disposed of and pollute the environment can be used for transesterification reactions. However, they need treatment to achieve high conversion rates. In this context, the aim of this work was to perform and analyze the treatment of residual frying oil with the evaporation and entrainment process, aiming at its use as raw material to obtain biodiesel (methyl esters) by a transesterification reaction. The physicochemical properties of the residual oil after treatment were characterized by moisture content, pH and the acidity, saponification, iodine, and peroxide index. The conversion rate of the residual oil to methyl esters was determined by 1H NMR analysis. After the treatment, the method of analysis of variance showed that the oil obtained a significant reduction of the saponification, iodine, peroxide and acidity indexes, being the acidity reduced from 9.36 to 7.85 mg KOH g-1. The moisture content of 0.733% and elevation of pH to 8.0. The conversion rate of fatty acid biodiesel of residual oil was 79.3 %, lower value of standards norms (ASTM, 2005; EN, 2008; ANP, 2014), showing that the assigned methodology for frying residual oil is inefficient in biodiesel production.