Application and evaluation of a high-resolution mass spectrometry screening method for veterinary drug residues in incurred fish and imported aquaculture samples

Abstract

The ability to detect chemical contaminants, including veterinary drug residues in animal products such as fish, is an important example of food safety analysis. In this paper, a liquid chromatography high-resolution mass spectrometry (LC-HRMS) screening method using a quadrupole-Orbitrap instrument was applied to the analysis of veterinary drug residues in incurred tissues from aquacultured channel catfish, rainbow trout, and Atlantic salmon and imported aquacultured products including European eel, yellow croaker, and tilapia. Compared to traditional MS methods, the use of HRMS with nontargeted data acquisition and exact mass measurement capability greatly increased the scope of compounds that could be monitored simultaneously. The fish samples were prepared for analysis using a simple efficient procedure that consisted of an acidic acetonitrile extraction followed by solid phase extraction cleanup. Two different HRMS acquisition programs were used to analyze the fish extracts. This method detected and identified veterinary drugs including quinolones, fluoroquinolones, avermectins, dyes, and aminopenicillins at residue levels in fish that had been dosed with those compounds. A metabolite of amoxicillin, amoxicillin diketone, was also found at high levels in catfish, trout, and salmon. The method was also used to characterize drug residues in imported fish. In addition to confirming findings of fluoroquinolone and sulfonamide residues that were found by traditional targeted MS methods, several new compounds including 2-amino mebendazole in eel and ofloxacin in croaker were detected and identified. Graphical Abstract Aquacultured samples are analyzed with a high-resolution mass spectrometry screening method to detect and identify unusual veterinary drug residues including ofloxacin in an imported fish.

Comparison of data acquisition modes with Orbitrap high‐resolution mass spectrometry for targeted and non‐targeted residue screening in aquacultured eel

“…Standards for these analytes were purchased from Sigma‐Aldrich, and individual stock standards were prepared in methanol, water, or acetonitrile at a concentration of approximately 100 μg/mL as the free base or acid. To fortify fish samples at the target testing levels that are based on the US FDA Chemotherapeutics in Aquaculture Compliance Program and indicated in Table , two intermediate working solutions (“stable” and “unstable”) were prepared and added to fish tissue as previously described …”

“…The LC conditions used are the same as described previously . The LC separation was performed on a Supelco Ascentis Express C18 column (7.5 cm × 2.1 mm, 2.7 μm).…”

“…The LC conditions used are the same as described previously. 8,9 The LC separation was performed on a Supelco Ascentis Express C18 column (7.5 cm × 2.1 mm, 2.7 μm). The mobile phase (0.3 mL/min) consisted of 0.1% formic acid (A) and acetonitrile (B).…”

“…Aquacultured eels are especially susceptible to the use of chemotherapeutics because they are often raised in confined spaces such as tanks or barrels . Numerous drug residues, including antibiotics and anthelmintics, have been detected in imported eel samples . Eel can also be highly processed making it a difficult matrix to analyze.…”

“…35 Numerous drug residues, including antibiotics and anthelmintics, have been detected in imported eel samples. 8,9 Eel can also be highly processed 36 making it a difficult matrix to analyze. Therefore, eel is an appropriate and challenging matrix to use as a test case for the evaluation of various HRMS data acquisition programs for the detection of both targeted and non-targeted chemical contaminants.…”