AlcoLab: a method for methanol screening using density and syringe-flow measurements, implemented as an open-source application
- 1Baru Tech, Brasília, DF, Brazil
- 2Universidade Federal do Maranhão (UFMA), Centro de Ciências Exatas e Tecnologia (CCET), Campus Bacanga, São Luís, MA, Brazil
- 3Universidade Federal do Maranhão (UFMA), Centro de Ciências de Chapadinha, Chapadinha, MA, Brazil
Abstract
Methanol adulteration in alcoholic beverages remains a recurrent public health problem. Instrumental methods for detecting methanol are not always available in field settings, while colorimetric methods often require toxic or hazardous reagents. Here we present AlcoLab, a proof-of-concept method for semiquantitative methanol screening in hydroalcoholic mixtures using a balance readable to 0.1 g and a 20-mL disposable syringe fitted with a 22-gauge needle. A ternary viscosity grid was fitted and selected using literature data (46-point model-selection benchmark: MAE ≈ 0.043 mPa·s; MAPE ≈ 2.47%), together with an empirical model linking syringe-flow response to viscosity. Under conditional blocked evaluation over 54 eligible replicates — including 30 measurements in commercial distilled spirits and commercial ethanol, 14 of which were methanol-spiked — the model yielded a MAE of 0.026 for the methanol mass fraction and flagged all 26 methanol-containing replicates, at a 26% false-positive rate over 84 negative predictions. Because the inversion was constrained to a ±2 percentage-point window around the nominal total alcohol content, these figures characterize the flow and inversion stages; all positives contained more than 16% methanol by mass, so performance at low methanol fractions remains to be established. The method is distributed as an open-source progressive web app (alcolab.org; AGPL-3.0) for methanol screening in suspected samples of distilled spirits and commercial ethanol solutions.•Reagent-free methanol screening by density, syringe-flow measurements, and ternary inversion.
•Open-source AlcoLab application, with statistical interpretation and traffic-light classification.
•Reproducible workflow with a ternary grid, rerunnable scripts, and supplementary videos.
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BibTeX
@article{souza2026alcolab,
title = {{AlcoLab: a method for methanol screening using density and syringe-flow measurements, implemented as an open-source application}},
author = {Diego Mendes de Souza and Pedro Augusto de Oliveira Morais and Nayara Ferreira Santos and Romério Rodrigues dos Santos Silva},
journal = {MethodsX},
year = {2026},
month = oct,
doi = {10.1016/j.mex.2026.104211},
url = {https://doi.org/10.1016/j.mex.2026.104211},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - AlcoLab: a method for methanol screening using density and syringe-flow measurements, implemented as an open-source application
AU - Diego Mendes de Souza
AU - Pedro Augusto de Oliveira Morais
AU - Nayara Ferreira Santos
AU - Romério Rodrigues dos Santos Silva
PY - 2026
DA - 2026/10/19
JO - MethodsX
DO - 10.1016/j.mex.2026.104211
UR - https://doi.org/10.1016/j.mex.2026.104211
AB - Methanol adulteration in alcoholic beverages remains a recurrent public health problem. Instrumental methods for detecting methanol are not always available in field settings, while colorimetric methods often require toxic or hazardous reagents. Here we present AlcoLab, a proof-of-concept method for semiquantitative methanol screening in hydroalcoholic mixtures using a balance readable to 0.1 g and a 20-mL disposable syringe fitted with a 22-gauge needle. A ternary viscosity grid was fitted and selected using literature data (46-point model-selection benchmark: MAE ≈ 0.043 mPa·s; MAPE ≈ 2.47%), together with an empirical model linking syringe-flow response to viscosity. Under conditional blocked evaluation over 54 eligible replicates — including 30 measurements in commercial distilled spirits and commercial ethanol, 14 of which were methanol-spiked — the model yielded a MAE of 0.026 for the methanol mass fraction and flagged all 26 methanol-containing replicates, at a 26% false-positive rate over 84 negative predictions. Because the inversion was constrained to a ±2 percentage-point window around the nominal total alcohol content, these figures characterize the flow and inversion stages; all positives contained more than 16% methanol by mass, so performance at low methanol fractions remains to be established. The method is distributed as an open-source progressive web app (alcolab.org; AGPL-3.0) for methanol screening in suspected samples of distilled spirits and commercial ethanol solutions.•Reagent-free methanol screening by density, syringe-flow measurements, and ternary inversion. •Open-source AlcoLab application, with statistical interpretation and traffic-light classification. •Reproducible workflow with a ternary grid, rerunnable scripts, and supplementary videos.
SN - 2215-0161
ER -