Multi-component analysis of tetracyclines, sulfonamides and tylosin in swine manure by liquid chromatography-tandem mass spectrometry.
A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure for three classes of antibiotic-tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75 degrees C and 2,500 psig in three steps using two cycles with 0.2 mol L(-1) citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L(-1) citric acid (pH 3). After liquid-liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3 with formic acid and the sample was vacuum-filtered through 0.6 mum glass-fibre filters. Finally the samples were pre-concentrated by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50-5,000 microg kg(-1) dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42-54%), sulfadiazine (59-73%), and tylosin (9-35%) and did not vary with concentration or from day-to-day. Limits of quantification (LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10-100 microg kg(-1) dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts were found for tetracyclines (up to 30 mg kg(-1) dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg(-1) dry matter (SDZ); tylosin was not detected in any samples.
Jacobsen
Anne Marie
AM
Department of Pharmaceutical and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, 2 Universitetsparken, 2100 Copenhagen, Denmark. amja@dfuni.dk
Halling-Sørensen
Bent
B
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D008372:Manure / Q000032:analysis*; D011312:Pressure; D012680:Sensitivity and Specificity; D013449:Sulfonamides / Q000032:analysis*; D013552:Swine; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013696:Temperature; D013754:Tetracyclines / Q000032:analysis*; D013997:Time Factors; D015645:Tylosin / Q000032:analysis*
D008372:Manure; D013449:Sulfonamides; D013754:Tetracyclines; D015645:Tylosin