Multiclass accurate mass screening of veterinary drugs in animal tissue - value of enhanced sensitivity and resolution for reliable identification

摘要

A sensitive and reliable method for the screening and quantitation of various classes of veterinary drugs in meat extract by UHPLC-(Q)TOF has been established. Optimization of the sample preparation and of the UHPLC separation resulted in lower matrix interferences. The impact of higher instrument sensitivity as well as of increased resolving power on the discovery rate of veterinary drugs spiked in muscle tissue has been compared. It has been shown that a resolution of > 15,000 FWHM reduced matrix interferences with target compounds and reference mass ions, thus giving better mass accuracies. By using new dual spray Agilent Jet Stream, sensitivity as well as reference mass introduction has been improved significantly resulting in high quality data even in high background matrices. In combination with the dual ion funnel interface the reliable identification of banned and not authorized compounds for which a MRPL of 1 (mu)g/kg has been set, could be achieved. Data evaluation has been done using the "Find-by-Formula" data mining algorithm in combination with an accurate mass database. By including retention times as well as additional fragments into the database false positive detection rate could be reduced to a minimum. Preliminary validation experiments demonstrated typical analyte real recoveries from 40 to 80percent. The presentation shows that UHPLC/QTOF is a suitable technique for routine screening of a wide range of veterinary drugs in muscle tissue.