Development and validation of a GC-MS method for the simultaneous detection of preservatives in pharmaceuticals, food preparations and natural products

Identification and quantification of preservatives, used in pharmaceutical and cosmetic products as well as in foods and beverages to increase stability and shelf life, is one of the main challenges of analytical chemistry. This study shows a real field application of a GC-MS method that was developed and validated for the simultaneous determination of methyl paraben, propyl paraben, ethyl paraben, butyl paraben, benzoic acid, benzyl alcohol, and sorbic acid in semisolid and liquid preparations. All the analytes showed correlation coefficients (r²) > 0.999 for linearity. Lower limit of quantification (LLOQ) values for methyl paraben, propyl paraben, ethyl paraben, butyl paraben, benzoic acid, benzyl alcohol, and sorbic acid were 10 ng, 14 ng, 15ng, 12 ng, 21 ng, 19 ng, and 24 ng, respectively. Percent recovery values for all the analytes were above 90% in the samples, and intraday/interday reproducibility were assessed. Relative standard deviation (RSD) values for accuracy and precision were found within ICH guidelines range. The content of preservatives in screened samples (100) was correlated with microbial growth. The method, validated in terms of linearity, accuracy, and precision, can be efficiently applied to the evaluation of commercial products.