An optimized method for the accurate determination of patulin in apple products by isotope dilution-liquid chromatography/mass spectrometry

Abstract

Patulin, a mycotoxin produced by several molds in fruits, has been frequently detected in apple products. Therefore, regulatory bodies have established recommended maximum permitted patulin concentrations for each type of apple product. Although several analytical methods have been adopted to determine patulin in food, quality control of patulin analysis is not easy, as reliable certified reference materials (CRMs) are not available. In this study, as a part of a project for developing CRMs for patulin analysis, we developed isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC/MS/MS) as a higher-order reference method for the accurate value-assignment of CRMs. (13)C7-patulin was used as internal standard. Samples were extracted with ethyl acetate to improve recovery. For further sample cleanup with solid-phase extraction (SPE), the HLB SPE cartridge was chosen after comparing with several other types of SPE cartridges. High-performance liquid chromatography was performed on a multimode column for proper retention and separation of highly polar and water-soluble patulin from sample interferences. Sample extracts were analyzed by LC/MS/MS with electrospray ionization in negative ion mode with selected reaction monitoring of patulin and (13)C7-patulin at m/z 153→m/z 109 and m/z 160→m/z 115, respectively. The validity of the method was tested by measuring gravimetrically fortified samples of various apple products. In addition, the repeatability and the reproducibility of the method were tested to evaluate the performance of the method. The method was shown to provide accurate measurements in the 3-40 μg/kg range with a relative expanded uncertainty of around 1%.

Developments in the Monitoring of Patulin in Fruits Using Liquid Chromatography: an Overview

“…In some work, the authors have utilized LLE followed by SPE clean-up and LC-MS/MS quantification of patulin in apple juice, ground fruit, and jam using (Seo et al 2015). The method provides satisfactory LOQs in the range from 0.8 to 2.4 μg kg −1…”

“…The mobile phase composed of water and methanol or water and acetonitrile with addition of acetic acid (Tamura et al 2012;Hammami et al 2017) or ammonium acetate (Christensen et al 2009;Malachová et al 2014;Seo et al 2015;Vaclavikova et al 2015) is used for this mycotoxin analysis. Unfortunately, due to high polarity of target molecule, the LC-MS analysis suffers from low sensitivity.…”

“…This approach allows for isolation, concentration, as well as purification of target molecule. SPE has been appreciated by researchers studying patulin contamination in variety of fruit products (juices, purees, jams) and was used separately (Li et al 2007b;Funes and Resnik 2009;Catana et al 2011;Zhou et al 2012) or in combination with liquid-liquid extraction (Spadaro et al 2008;Barreira et al 2010;Zaied et al 2013;Karakose et al 2015;Seo et al 2015;De Clercq et al 2016) (Tamura et al 2012). Nevertheless, like any other technique, SPE has also some limitations.…”

Determination of trace patulin in apple-based food matrices

“…So, accurate determination was based on the equation for each specific matrix. Seo, Kim, and Baek (2015) also utilized HLB sorbent to purify samples, after LLE with ethyl acetate. The clean-up efficiency was improved greatly and the addition of isotopic IS further lowered the matrix effect.…”

Exact Matrix‐matching Calibration by Standard Addition‐Isotope Dilution‐Liquid Chromatography/Mass Spectrometry for the Accurate Determination of Chloramphenicol in Infant Formula

“…A post column infusion system as described in our previous articles was used to investigate matrix effects on the measurement of the CAP/CAP‐ d 5 ratio with the LC/MS method. The LC/MS system was operated as described in section “LC/MS analysis” but a constant flow (20 L/min) of a 20 µg/kg CAP standard solution was infused into the LC eluent via a T‐connector installed in front of the ESI interface.…”