Validation of a Method for Cylindrospermopsin Determination in Vegetables: Application to Real Samples Such as Lettuce (Lactuca sativa L.)

Abstract

Reports on the occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) have increased worldwide because of CYN toxic effects in humans and animals. If contaminated waters are used for plant irrigation, these could represent a possible CYN exposure route for humans. For the first time, a method employing solid phase extraction and quantification by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) of CYN was optimized in vegetables matrices such as lettuce (Lactuca sativa). The validated method showed a linear range, from 5 to 500 ng CYN g−1 of fresh weight (f.w.), and detection and quantitation limits (LOD and LOQ) of 0.22 and 0.42 ng CYN g−1 f.w., respectively. The mean recoveries ranged between 85 and 104%, and the intermediate precision from 12.7 to 14.7%. The method showed to be robust for the three different variables tested. Moreover, it was successfully applied to quantify CYN in edible lettuce leaves exposed to CYN-contaminated water (10 µg L−1), showing that the tolerable daily intake (TDI) in the case of CYN could be exceeded in elderly high consumers. The validated method showed good results in terms of sensitivity, precision, accuracy, and robustness for CYN determination in leaf vegetables such as lettuce. More studies are needed in order to prevent the risks associated with the consumption of CYN-contaminated vegetables.

New Method for Simultaneous Determination of Microcystins and Cylindrospermopsin in Vegetable Matrices by SPE-UPLC-MS/MS

“…In general, slightly better results have been obtained for MCs compared to CYN. Previously, high recoveries (104% for 20 µg L −1 ) were shown for CYN in a validated method for determination of this toxin in lettuce [ 40 ]; however, in the present work, CYN recovery percentages resulted in compromised favor of the extraction and detection of more hydrophobic cyanotoxins, such as MCs.…”

“…Considering previous experiments in which the lyophilization process did not affect the recovery of toxins [ 40 ], the addition of toxins to the lettuce leaves (fortification process before extraction) was performed with fresh weight lettuce and then they were lyophilized. First, before testing the extraction efficiency for the four cyanotoxins, the UPLC–MS/MS method was set up for this purpose, acquiring mass spectra and adjusting mobile phase strength for commercially available standard solutions of MC-LR, MC-RR, MC-YR, and CYN.…”

“…Specifically, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) allows excellent specificity and sensitivity for cyanotoxins’ detection and quantification in waters and in more complicated matrices, becoming the preferred technique for cyanotoxin analysis [ 16 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Previous studies were carried out in our laboratory for the determination of CYN in water [ 38 ], fish [ 39 ], and vegetables [ 40 ]. However, the separate isolation and identification of toxins belonging to each discrete class is laborious, expensive, and time consuming.…”

Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativa

“…The mean CYN concentration found in the leaves of lettuce exposed to the toxin, at 10 and 50 µg/L CYN, were 2.4 and 9.4 µg CYN/kg fw (Table 1), respectively, determined with the quantification method described by Prieto et al (2018) [64]. This means that the total amount of CYN taken-up, in relation to the amount present in the culture medium, varied between 23.7% and 18.8%, depending on the CYN concentration tested, and globally it could be considered around 20%.…”

Risk assessment methodologies in the field of contaminants, food contact materials, technological ingredients and nutritional risks

“…The same External scientific EFSA Report (Testai et al., ) showed the need for new analytical methods for sample preparation, routine detection and quantification of CYN and mixtures of MCs – CYN in complex matrices for both control procedures and risk assessment. Thus, the fellow participated in the activities related to the development and optimisation of a method to determine the content of CYN and MCs – CYN in mussel matrix based on a solid‐phase extraction method and quantification by ultra‐performance liquid chromatography–tandem mass spectrometry previously optimised and validated by the team at DNBTLM (Diez‐Quijada et al., ; Prieto et al., ). The fellow gained a close insight into the developing and validating of analytical methods with suitable limit of quantification (LOQ) and limit of detection (LOD) for risk assessment purposes.…”