Evaluation of Quantification Methods to Compensate for Matrix Effects in the Analysis of Benzalkonium Chloride and Didecyldimethylammonium Chloride in Fruits and Vegetables by LC-ESI-MS/MS

Abstract

Given the extensive presence of some toxic quaternary ammonium compound residues in foodstuffs arriving into the EU during 2012, the Food Authority Control of Geneva decided to implement a monitoring plan to investigate the presence of these contaminants in food: a method based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and liquid chromatography electrospray tandem mass spectrometry was developed for analyzing didecyldimethylammonium chloride and four benzalkonium chloride homologue residues in fruits and vegetables. An in-house method validation, based on the SANCO guidelines (Document SANCO No. 12571/2013), was conducted using three independent series in orange, lettuce, and avocado composite samples spiked at three levels (10, 100, 500 μg/kg). Trueness and precision were calculated by pooling all results at each concentration level to account for the variability among fruits and vegetables. To avoidmatrix effects on quantitative results, five quantification strategies were investigated: (i)solvent calibration, (ii) matrix-matched calibration prepared on samples and (iii) on sample extract aliquots, and (iv) standard addition prepared on samples and (v) on sample extract aliquots. Due to the nonlinear instrumental response for the large concentration range investigated, a quadratic calibration model was mandatory for all approaches. Solvent calibration gave very poor recoveries due to the high signal suppression caused by matrix effects. Smaller biases were observed for matrix-matched calibrations; however, these results exhibited relatively low precision. Both of the standard addition methods compensated for matrix effects and provided accurate analytical results. Due to the ease of its implementation, the matrix standard addition method, where analytes are added to sample extract aliquots, was preferred over the classical standard addition in samples. Nonlinear extrapolations appeared to be particularly effective in obtaining good results for both standard addition methods when the calibration curve was convex or very slightly concave. The resulting validated method was used to monitor 108 fruit and vegetable commercial samples in May 2013

Unraveling Enterococcus susceptibility to quaternary ammonium compounds: genes, phenotypes, and the impact of environmental conditions

“…To assess the activity of QACs on Enterococcus growth or survival under diverse environmental conditions that mimic real contexts, MIC BC and MBC BC were determined in anaerobic conditions (e.g., occurring in sewage) ( 37 , 38 ), room temperature (22°C; representing abiotic surfaces in healthcare or agri-food sectors) ( 39 ), and mildly acidic pH (pH = 5; resembling human skin and fresh fruits/vegetables contaminated with QACs residues) ( 40 – 42 ). BC was the QAC chosen for the susceptibility assays with modified conditions, as both species demonstrated higher tolerance and phenotype variability (wider MIC and MBC ranges) to this compound compared to DDAC under standard conditions.…”

From fundamentals in calibration to modern methodologies: A tutorial for small molecules quantification in liquid chromatography–mass spectrometry bioanalysis

“…As mentioned in Section 2.4, FDA suggests performing a parallelism between SAM and surrogate matrix or analyte to justify their use, but they do not provide any information about the number of calibrants required for SAM. Considering the literature, most authors use between four and six spiked concentrations [96,[129][130][131]. As with the EC approach, the use of IS to correct for procedural errors is recommended when a sample preparation that is different from simple "dilute and shoot" is performed [130].…”

“…SAM can also be applied when the calibration curve is polynomial, particularly when high endogenous signals affect the linearity of the response due to detector saturation. For example, Díez et al showed that linear fitting provides adequate recoveries for antibiotic quantification in fruits and vegetables when concave SAM curves are obtained, while quadratic extrapolation could be used for convex or slightly concave curves [131].…”

Determination of 25 quaternary ammonium compounds in sludge by liquid chromatography–mass spectrometry

“…Hrubec [ 20 ] detected QACs in 80% of the subjects studied, indicating a clear relationship between QACs in blood and health-related biomarkers. Asthmatic reactions induced by BAC and DADMAC in QACs have been confirmed in a few cases via bronchial provocation tests [ 21 ]. A French physician-based notification program for work-related asthma [ 19 ] reported a marked increase in incident cases due to QACs, rising from 1.4% in 2001of reported cases in 2009 to 8.3%, mainly in the health and social sectors.…”