ANALYTICAL METHODS FOR METHANOL DETECTION IN ALCOHOLIC BEVERAGES: A COMPARATIVE REVIEW OF CLASSICAL, COLORIMETRIC, AND CHROMATOGRAPHIC APPROACHES
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.
Read ArticleSELF-ASSEMBLED MULTILAYERS OF WATER GLUCOSE MODIFIED-CHITOSAN AND GLUCOSE OXIDASE FOR DETECTION OF GLUCOSE IN MILK SAMPLES
Background: A crucial aspect of electrochemical enzymatic biosensor development is the immobilization of the enzymes, as it directly influences the sensitivity of the bioelectrode. Among the different methods used to incorporate enzymes on the surface of the transducers, layer-by-layer (LbL) self-assembly based on electrostatic interaction with polyelectrolytes of opposite charge stands out due to its simplicity and reproducibility. Aims: The aim of the work was to develop an electrochemical glucose biosensor by LbL assembly of a new functionalized chitosan polycation and the enzyme glucose oxidase (GOx). Methods: Chitosan was chemically functionalized with glucose by the Maillard reaction. The resulting polycation, named G-Chit, is soluble in the medium compatible with the enzyme. The bioelectrode was obtained by alternating adsorption of G-Chit and GOx onto carbon paste electrodes. By selecting the number of bilayer of G-Chit/GOX, the enzyme concentration, and the pH, the electroanalytical performance of the biosensor was optimized. The electrochemical responses were characterized by cyclic voltammetry and chronoamperometry. Results: Under optimized experimental conditions, the biosensor exhibited a sensitivity of (0.81 ± 0.03) µA mM-1 in a glucose concentration range of (0.18 to 1.75) mM. Discussion: Results indicated that catalytic response increases both with the number of G-Chit/GOx bilayers and the enzyme concentration, obtaining the best responses for 3 bilayers and 2 mg mL-1, respectively, while the optimum working pH value was 7.0. Conclusions: The analytical response of the biosensor was tested in milk samples with negligible matrix effects, suggesting a potential application in other dairy products. Results show that G-Chit appears promising for the immobilization of enzymes.
Read ArticleUNRAVELING THE COMPLEXITIES OF CARDIOVASCULAR MEDICINE: A CONVERSATION WITH DR. PETER MCCULLOUGH (EXTENDED EN-US VERSION)
Background: This interview covers Dr. Peter McCullough’s medical career, experience as an editor of medical journals, and his expertise in areas such as cardiomyopathy, myocarditis, and pericarditis. Aims: The primary aim is to understand Dr. McCullough’s perspectives on various medical topics, including his journey as a cardiologist, the importance of peer review, the phenomenon of Pheidippides cardiomyopathy, the differences between myocarditis and pericarditis, and the significance of ethical principles like the Nuremberg Code and the Declaration of Helsinki. Additionally, the interview aims to explore his concerns about censorship during the COVID-19 pandemic. Methods: The interview follows a question-and-answer format, with the interviewer posing questions to Dr. McCullough on various topics related to his medical career, research interests, and ethical considerations. Results: Dr. McCullough shares his insights on topics such as cardiomyopathy, myocarditis, and pericarditis, emphasizing the importance of peer review, identifying potential biases, and balancing scientific rigor with timely dissemination of findings. He also highlights the significance of the Nuremberg Code and the Declaration of Helsinki in ensuring informed consent and preventing coercion in medical research and treatment. Discussion: Dr. McCullough expresses concerns about censorship during the COVID-19 pandemic, which he believes impacted the ability of medical professionals to freely discuss and disseminate health-related information. He also discusses the potential role of COVID-19 vaccines in causing myocarditis and the need for transparent communication about treatment options and potential complications. Conclusion: The interview provides valuable insights from Dr. McCullough’s extensive medical experience and expertise, covering a range of topics from cardiovascular conditions to ethical principles and the challenges posed by censorship during the COVID-19 pandemic.
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