Multi-residue determination of micropollutants in Nigerian fish from Lagos lagoon using ultrasound assisted extraction, solid phase extraction and ultra-high-performance liquid chromatography tandem mass spectrometry

This study proposes a new, fast and sensitive multi-residue method for simultaneous screening of different classes of pharmaceuticals in fish using an ultrasonic assisted extraction (UAE) followed by solid phase extraction (SPE) as clean-up step and by ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The analysis was carried out by spiking ∼1 g wet tissue of sole fish muscle (Solea solea) with internal standards (IS) prior to extraction and quantitative analysis. The approach gave good relative recoveries, precision and accuracy for thirty six out of forty one compounds analysed with most compounds having method detection limits (MDLs) < 3 ng g-1 and method quantification limits (MQLs) < 29 ng g-1. Generally, compounds had relative recoveries between 46-113%, overall precision was <20% and accuracy > 75% for most compounds. The method was applied to determine levels of micropollutants in muscles, gills and eyes of seven fish species from the Lagos lagoon. Only three compounds: tramadol, trimethoprim and fluoxetine were detected in the fish samples. In general, measured concentrations were >MDLs with fluoxetine present in all fish tissues (except tilapia eyes and gills) at concentrations >MQL.