Fully automated screening of veterinary drugs in milk by turbulent flow chromatography and tandem mass spectrometry

Abstract

There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging to seven different classes were selected for this study. After developing and optimising the method, parameters such as linearity, repeatability, matrix effects and carry-over were studied. The screening method was then tested in the routine analysis of 12 raw milk samples. Even without internal standards, the linearity of the method was found to be good in the concentration range of 50 to 500 µg/L. Regarding repeatability, RSDs below 12% were obtained for all analytes, with only a few exceptions. The limits of detection were between 0.1 and 5.2 µg/L, far below the maximum residue levels for milk set by the EU regulations. While matrix effects—ion suppression or enhancement—are obtained for all the analytes the method has proved to be useful for screening purposes because of its sensitivity, linearity and repeatability. Furthermore, when performing the routine analysis of the raw milk samples, no false positive or negative results were obtained.

Development and validation of a turbulent flow chromatography and tandem mass spectrometry method for the quantitation of methotrexate and its metabolites 7-hydroxy methotrexate and DAMPA in serum

“…This loop contained a solvent mixture strong enough to elute the analytes from the TFC into the HPLC column. An eluting pump delivered a mixture of solvents and enabled a normal chromagraphic separation and detection [10]. …”

“…TFC-LC-MS/MS is a technique that has been shown to eliminate much time-consuming sample processing and increase productivity and throughput [10]. TFC uses high mobile phase flow rates over large porous particles (30–60 μM).…”

Identification of new transformation products during enzymatic treatment of tetracycline and erythromycin antibiotics at laboratory scale by an on-line turbulent flow liquid-chromatography coupled to a high resolution mass spectrometer LTQ-Orbitrap

“…The turbulence inside the extraction column (flow P1.5 mL min À1 ) allows the good removal of high molecular weight compounds, whereas small molecules are trapped by the column pores, being a mixed mechanism of sorption and size exclusion chromatography (Thermo Scientific; Llorca, 2012). This technique has been used for the analysis of pharmaceuticals, their metabolites and known transformation products in environmental water samples (López-Serna et al, 2012) or for the analysis of more complicated matrices such as food (Mottier et al, 2007;Stolker et al, 2010). In addition to the common techniques based on the detection of known antibiotics in the environment, different analytical methodologies are being developed in order to detect and identify ''new'' contaminants and unknown substances that reach WWTPs through the so-called non-target analysis (Krauss et al, 2010).…”

Current Trends in Sample Treatment Techniques for Environmental and Food Analysis

“…Turboflow chromatography has also been described for sample treatment in the screening of eight veterinary drugs in milk [15]. Protein precipitation was induced before analyzing samples of whole, skimmed and semi-skimmed milk samples.…”

“…The QuEChERS method is a recent and fascinating alternative procedure that has become particularly popular for the multi-residue analysis of pesticides in various food matrices [9,10], although this methodology is also being successfully employed for the extraction of other families of compounds [11,12]. Recently, the use of turbulent-flow chromatography (TFC) has also been reported for direct analysis of complex matrices such as honey, milk and animal tissues with reduced or without any sample manipulation [13][14][15].…”