Determinação de álcoois tóxicos em alimentos e medicamentos empregando cromatografia a gás acoplada à espectrometria de massas.

Abstract

The development and validation of analytical methods employing adequate techniques are crucial to obtain information related to the quality of medicine and food, aiming to guarantee the safety of their consumption. Compounds of the ethylene glycol class, such as ethylene glycol and diethylene glycol, and other toxic alcohols like methanol, have high toxicity in humans when ingested. Only five studies of analytical methods for diethylene glycol in foods were found in scientific databases, and only one of them used the GC-MS technique and none applied the simultaneous quantification of ethylene glycol and diethylene glycol. Although there are some studies for the simultaneous determination of ethylene glycol and diethylene glycol in glycerin and propylene glycol by GC-FID, multianalyte methods were not found in the literature for ethylene glycol, diethylene glycol and methanol in glycerin, propylene glycol and syrups by GC-MS, a more selective technique with greater detectability. Aiming to overcome the limitations of analytical methods described in the literature, in the present work multianalyte methods were developed and validated using simple dilution of the sample and quantification by GC-MS, with electronic impact ionization, in the analysis of contaminants (ethylene glycol and diethylene glycol in beers; ethylene glycol, diethylene glycol and methanol in glycerin, propylene glycol and pharmaceutical syrups). All figures of merit were met in validation The methods proved to be selective. The linear regressions of the calibration curves were statistically significant, with the minimum value for the correlation coefficients being 0.990. The methods showed satisfactory accuracy and precision at all concentration levels analyzed for all analytes. The limits of and quantification were considered appropriate for the purpose of the analysis. An uncertainty model was developed. It was found that the percentual expanded uncertainty in samples fortified in the concentration of limit of quantitation was at about 30% and the main contributions to the uncertainty of the result was the absence of correction of the results by anayte recovery and the intermediate precision. The method for beer analysis , employed in a real inspection action, detect and/or quantify the presence of ethylene glycol and diethylene glycol in 51 beer samples, coming from just one manufacturer, among 701 samples analyzed, which allowed the removal of more than 80 thousand liters of contaminated beer in Brazil. Finally, the presence of ethylene glycol and diethylene glycol was detected at levels below the method's quantification limit in a sample of an oral solution, indicated for adult and pediatric use, among 36 samples of pharmaceutical syrups, solutions, suspensions and oral emulsions analyzed. This finding highlights the importance of implementing quality control analyzes of glycerin and propylene glycol to search for toxic alcohols.