Development of a Low-Temperature Purification Method for Gas Chromatography–Mass Spectrometry Quantification of Three Cresol Isomers in Smoked Bacon

Cresol isomers are compounds known as environmental chemical contaminants, and they are widely distributed in smoked foods. Thus, the objective of this study was to develop a method based on solid–liquid extraction with low-temperature purification (SLE-LTP) and analysis by gas chromatography-mass spectrometry (GC–MS) for quantification of three cresol isomers (o-cresol, m-cresol, and p-cresol) in smoked bacon samples. The SLE-LTP was optimized, validated, and compared with the QuEChERS method. The proposed method was selective after derivatization with BSTFA [N,O-Bis(trimethylsilyl)trifluoroacetamide], which achieved a limit of quantification of 53.3 μg kg⁻¹, recoveries between 90 and 116%, relative standard deviation lower than 13%, negative matrix effects, and linearity in the range of 53.3 to 1332.5 μg kg⁻¹ with coefficient of determination higher than 0.99 in matrix-matched calibration. The method was applied to quantify cresol isomers in five commercial samples of smoked bacon and the results showed concentrations between 62.1 and 1204 μg kg⁻¹. Finally, the developed methodology is suitable for monitoring cresol isomers, which are present in high levels in smoked bacon.