Qualitative Screening of Undesirable Compounds from Feeds to Fish by Liquid Chromatography Coupled to Mass Spectrometry

Abstract

This article describes the development, validation and application of a rapid screening method for the detection and identification of undesirable organic compounds in aquaculture products. A generic sample treatment was applied without any purification or preconcentration step. After extracting the samples with acetonitrile/water 80:20 (0.1% formic acid), the extracts were centrifuged and directly injected in the LC-HRMS system, consisting of ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). A qualitative validation was carried out for over 70 representative compounds, including antibiotics, pesticides and mycotoxins, in fish feed and fish fillets spiked at 20 µg/Kg and 100 µg/Kg. At the highest level, the great majority of compounds were detected (using the most abundant ion, typically the protonated molecule) and unequivocally identified (based on the presence of two accurate-mass measured ions). At the 20 µg/Kg level, many contaminants could already be detected although identification using two ions was not fully reached for some of them, mainly in fish feed due to the complexity of this matrix. Subsequent application of this screening methodology to aquaculture samples made it possible to find several compounds from the target list, such as the antibiotic ciprofloxacin, the insecticide pirimiphos-methyl and the mycotoxins fumonisin B2 and zearalenone. A retrospective analysis of accurate-mass full-spectrum acquisition data provided by QTOF MS was also made, without neither reprocessing nor injecting the samples. This allowed the detection and tentative identification of other organic undesirables different than those included in the validated list.

Tutorial review on validation of liquid chromatography–mass spectrometry methods: Part I

“…For the analysis of emerging environmental contaminants (e.g. residues of personal care products and pharmaceuticals) qualitative screening methods based on liquid chromatography coupled to high resolution mass spectrometer (LC-HRMS) have proven to be especially suited [104,105]. Both screening and confirmatory methods have to be validated.…”

“…Validation of screening methods is not within the scope of this review and interested reader is directed to the following works: [104][105][106][107]. Clearly, analyzing selected samples twice is disadvantageous with respect to workload and methods, which are able to screen and confirm in one run are most welcome.…”

Occurrence and potential transfer of mycotoxins in gilthead sea bream and Atlantic salmon by use of novel alternative feed ingredients

“…Up to 18 mycotoxins, AFB1, AFB2, AFG1, AFG2, OTA, NEO, FB1, FB2, FB3, T-2, DIA, ZEN, NIV, DON, 3-AcDON, 15-AcDON, Fus X, and HT-2 were analysed according to the methodology of Beltrán et al (2013), adapted to the aquaculture matrices (Nácher-Mestre et al, 2013). Briefly, 2.5 g homogenized samples were extracted with acetonitrile:water 80:20 (1% HCOOH) using an automatic mechanical shaker for 90 min.…”

“…Earlier studies established feasible analytical approaches for mycotoxins in feed ingredients, aquafeeds and fish fillets (Beltrán et al, 2013;Nácher-Mestre et al, 2013;Malachová et al, 2014). Based on this previous experience, the present work aims to quantify a wide range of mycotoxins in commercially available plant and PAP feed ingredients, fish feeds based on these ingredients, and their transfer to the edible part of farmed Atlantic salmon and gilthead sea bream, two main species of the European aquaculture.…”

Comment on “Contaminant levels in Norwegian farmed Atlantic salmon (Salmo salar) in the 13-year period from 1999 to 2011” by Nøstbakken et al.

“…In contrast to marine oils, vegetable oils generally contain low levels of dioxins and dl-PCBs but also are deficient in the very long-chain omega-3 fatty acids. An issue of concern is that the use of vegetable ingredients can introduce new chemicals like pesticides and polycyclic aromatic hydrocarbons (PAHs) as well as mycotoxins (Berntssen et al, 2010;Nacher-Mestre et al, 2013.…”