To study the presence of residues of pharmaceuticals in samples from a marine environmental ecosystems a simple and sensitivity method by high performance liquid chromatography coupled to quadrupole time of flight mass spectrometry detection (LC-ESI-QTOF-MS) have been optimized. Twenty-six selected pharmaceuticals (corresponding to 8 therapeutic families) were analyzed in clam Scrobicularia plana using an enzymatic-microwave assisted extraction. Sulphonamides (sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole); trimethoprim, an antibiotic that is frequently co-administered with sulfamethoxazole; anfenicols (chloramphenicol, florfenicol and thiamphenicol); fluoroquinolones (ciprofloxacin, enrofloxacin, flumequine, danofloxacin, gatifloxacin, norfloxacin, marbofloxacin and grepafloxacin); penicillins (amoxicillin); tetracyclines (chlortetracycline and oxytetracycline); non-steroidal anti-inflammatory drugs (salicylic acid, ketoprofen, naproxen, diclofenac and ibuprofen); beta-blocker drugs (atenolol); and antiepileptics (carbamazepine) were analyzed. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (50 mm x 2.1 mm, 1.7 μm). The mobile phase consisted of water (A) and acetonitrile (0.1 % formic acid) (B). A gradient elution program was performed over ten minutes. Initially, it was applied a 4.5 min linear gradient from 90% A to a 45% A, then a 3.5-min hold step returning to initial conditions at t= 8.0 min. 2 min were waited for equilibration before the following injection. The flow a rate was set at 0.4 mL min-1. Detection was carried out with a Xevo G2S QTOF mass spectrometer, in full scan resolution mode and ESI positive/negative ionization mode was applied. A 0.1 g lyophilized sample was extracted with 2 mL of acetonitrile: water 1:1 (v/v) solution, 10 μL proteinase-K and 1 mL of formic acid, by applying microwave energy (5 min, 50 W power). The extract was centrifuged for 10 min at 7000 rpm, the supernatant was evaporated under N2 stream and the residue was reconstituted with 1 mL of 0.1 % formic acid aqueous solution. The procedure was applied to samples from the Natural Park Bahía de Cádiz (San Pedro River). The results showed the presence of trace levels of ciprofloxacin and flumequine (detected and/or quantified).

Determination of residues of pharmaceuticals in clam Scrobicularia Plana by LC-ESI-QTOF-MS

ACS Spring Meeting 2021

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