Quantification of benzoic acid in beverages: the evaluation and validation of direct measurement techniques using mass spectrometry

Abstract

Orange juice is one of the most consumed beverages around the world and one of the most important export products in Brazil. Juice is a perishable good and industrial processing is generally carried out with the aim of increasing the lifetime of the product enabling its distribution worldwide. One extremely common process used for preservation is the addition of chemical preservatives such as benzoic acid. This addition has to be controlled to maintain safe levels and not to give the product a bad taste. Many analytical methods are available for the analysis of this compound in beverages; however, these methods tend to be laborious and long, involving tedious sample preparation steps. In this study, direct methods using mass spectrometry were evaluated for the rapid analysis of this compound. Two rapid methods were then developed are as follows: one using dilute and shoot preparation with flow injection analysis coupled to tandem mass spectrometric detection and another using headspace sampling gas chromatography coupled to mass spectrometry with very little sample preparation; both methods used isotope dilution calibration. Both methods were validated and metrologically evaluated using certified reference materials and applied to real samples of different types of beverages, including orange juice, soft drink, soy drink and orange flavored drink. Both methods present excellent performance in all cases and were rapidly performed, serving as references for laboratories, which might want to implement these methods in their routine analyses.