The development and validation of a multiclass liquid chromatography tandem mass spectrometry (LC-MS/MS) procedure for the determination of veterinary drug residues in animal tissue using a QuEChERS (QUick, Easy, CHeap, Effective, Rugged and Safe) approach.

A novel rapid multiresidue/multiclass procedure with liquid chromatography tandem mass spectrometry (LC-MS/MS) detection has been developed to screen for the presence of veterinary drug residues in animal tissues. The method uses a new sample preparation procedure loosely based on QuEChERS (QUick, Easy, CHeap, Effective, Rugged and Safe) methodology. Validation to date has been restricted to chicken muscle and has been performed according to European Commission guidelines [COMMISSION DECISION of 12 August 2002 implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results] for nitroimidazoles, sulphonamides, fluoroquinolones, quinolones, ionophores and dinitrocarbanilide. Recent work has shown that the method is also applicable to macrolide and lincosamide antibiotics, benzimidazoles, levamisole, avermectins and tranquillisers.

Multiresidue determination of triarylmethane and phenothiazine dyes in fish tissues by LC-MS/MS.

The occurrence of residues of malachite green and its leuco-metabolite in tissues of farmed fish for human consumption have long been of concern and there is extensive literature on methods of analysis and surveillance for these compounds. Recently, concern has been expressed that the use of other related compounds in place of malachite green may go undetected. This paper describes a new method for extending the range of triarylmethane and related phenothiazine dyes that can be detected in fish. In this procedure 13 parent compounds are monitored, with any potential leuco-forms being oxidized back to the parent prior to determination. The method utilizes a buffer-acetonitrile extraction followed by liquid-liquid extraction. Oxidant is added and the extracts further purified by cation exchange chromatography. Final determination is carried out using LC-MS/MS. The method has been validated to the standards of Commission Decision 2002/657/EC.

Simultaneous determination of six major ergot alkaloids and their epimers in cereals and foodstuffs by LC-MS-MS.

This paper describes a new and rapid method for accurate quantification of the six ergot alkaloids, ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, and ergocornine, by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The six ergot alkaloids studied have been defined by the European Food Safety Authority (EFSA) as among the most common and physiologically active ones. In addition, the method enables the quantification of the corresponding six epimers (ergo-inines) of these ergot alkaloids. This is of considerable importance in terms of the differences in toxicity of the isomeric forms. The method involves extraction under alkaline conditions using a mixture of acetonitrile and ammonium carbonate buffer followed by a rapid clean-up using dispersive solid-phase extraction with PSA (primary secondary amine) and a short chromatographic LC-run (21 min) with subsequent MS-MS detection. The method was developed and validated using ten different cereal and food samples. The major strength of the new method compared with previously published techniques is the simplicity of the clean-up procedure and the short analysis time. The limits of quantification were 0.17 to 2.78 µg kg(-1) depending on the analyte and matrix. Recovery values for the 12 ergot alkaloids spiked into ten different matrices at levels of 5, 50, and 100 µg kg(-1) were between 69 and 105% for 85 of 90 recovery measurements made over six days. Measurement uncertainty values were highly satisfactory. At a concentration level of 5 µg kg(-1) the expanded measurement uncertainty ranged from ±0.56 to ±1.49 µg kg(-1), at a concentration level of 100 µg kg(-1) the expanded measurement uncertainty ranged from ±8.9 to ±20 µg kg(-1). Both LOQs and measurement uncertainties were dependent on the analyte but almost independent of the matrix. The method performance was satisfactory when tested in a mini-intercomparison study between three laboratories from three different countries.