Publications by authors named "Lohanna Pereira El Haddad"

2 Publications

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Quantifying ethanol in ethanol-based hand sanitizers by headspace gas chromatography with flame ionization detector (HS-GC/FID).

J AOAC Int 2021 Sep 21. Epub 2021 Sep 21.

Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto-Universidade de São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto-, SP, 14040-900, Brazil.

Background: The COVID-19 pandemic sharply increased the demand for ethanol-based gel hand sanitizers, leading to a shortage of these products. Consequently, regulatory health agencies worldwide have altered their regulatory guidelines, on ethanol quality, to meet this high demand, raising concern about the products quality.

Objective: The aim of this study was to quantify ethanol content and to qualitatively assess common impurities in ethanol-based gel hand sanitizers by headspace gas chromatography with flame ionization detector (HS-GC/FID).

Methods: To quantify the ethanol content, 0.10 g of the sample was weighed in a 20 mL headspace vial and 5 mL of deionized water was added. Regarding the qualitative approach, 0.25 g of the sample was weighed and 4 mL of deionized water and was added. The samples were incubated, and then 400 µL of the headspace was injected into the GC/FID. Forty-eight products purchased in Brazil were analyzed.

Results: Thirteen products presented at least one nonconformity regarding the ethanol quantity. Two samples presented an average ethanol concentration below the lower limit considered effective. Twelve samples presented acetaldehyde or ethyl acetate.

Conclusion: The huge demand for ethanol-based gel hand sanitizers may have impacted their quality. Because concern with proper hand hygiene tends to remain an issue for a long period, more studies about quality control of hand sanitizers will be needed.

Highlights: A simple and fast HS-GC/FID method to quantify ethanol in ethanol-based gel hand sanitizers was developed, validated and applied to commercial samples in Brazil. The regulatory authorities must be more vigilant to ensure that the commercially available products meet the recommended specifications.
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September 2021

Pre-workout supplements marketed in Brazil: Caffeine quantification and caffeine daily intake assessment.

Drug Test Anal 2021 Apr 9. Epub 2021 Apr 9.

Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.

The stimulating and performance-enhancing properties of caffeine are often explored in one the most consumed types of supplements: the pre-workout supplements (PWS). However, despite the popularity of PWS, previous studies have reported incompatibilities between what is described in their labels and their actual caffeine content. This study aimed to develop, to optimize, and to validate a gas-chromatography coupled to nitrogen-phosphorus detector (GC-NPD) method to quantify caffeine in PWS and to analyze commercial PWS marketed in Brazil to estimate the caffeine daily intake. For this purpose, three different extraction procedures were evaluated: agitation in vortex, shaker, and sonication. Sonication yielded the best extraction results. Next, the parameters' temperature and time were optimized by using central composite rotatable design (CCRD) and response surface methodology, which revealed the optimal values of 70°C and 10 min. The method was validated and applied to quantify caffeine in 52 PWS. From the 36 PWS labels that specified the caffeine amount, seven (19%) presented more than 120% of the declared quantity, whereas 15 (42%) contained less than 80% of the labeled caffeine. Additionally, six products presented undeclared caffeine. Considering the label stated doses, five supplements exceeded the safe caffeine daily intake (400 mg). On the basis of these findings, supplement quality control remains an issue that deserves more attention from consumers, manufacturers, and regulatory agencies. Finally, we suggest that PWS consumers be careful of the habit of ingesting caffeine through other sources and avoid ingesting two or more different PWS products in the same day.
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April 2021