Simultaneous Determination of  -Agonists and Psychiatric Drugs in Feeds by LC-MS-MS

Abstract

A method was developed for the simultaneous determination of nine β-agonists (cimaterol, ractopamine, terbutaline, zilpaterol, salbutamol, clenbuterol, mabuterol, bambuterol and brombuterol) and six psychiatric drugs (diazepam, nitrazepam, oxazepam, chlorpromazine, promethazine and perphenazine) in animal feed by using solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Conditions were optimized for the extraction of the target analytes from animal feed and for clean-up with MCX SPE cartridges. The eluent was evaporated to dryness under nitrogen, and the residue was dissolved in a solution of acetonitrile and 1% formic acid (2:8, v/v) and analyzed by LC-MS-MS using an isotopic internal standard for quantification. Under the optimum conditions, the recovery values of the target analytes were between 70.1 and 110%, with coefficients of variation between 1.9 and 18.4%. The method was very reliable for the simultaneous determination of nine β-agonists and six psychiatric drugs in animal feed.

Development and Application of a Method for Rapid and Simultaneous Determination of Three β-agonists (Clenbuterol, Ractopamine, and Zilpaterol) using Liquid Chromatography-tandem Mass Spectrometry

“…The FSIS method comprises eight steps and does not include solid phase extraction and deproteinization steps, as is the case in our method ( United States Department of Agriculture Food Safety and Inspection Service Office of Public Health Science, 2014 ). Notably, there are additional examples of methods that do not use deproteinization steps for the analyses of feed and milk ( Li et al ., 2010 ; Suo et al ., 2013 ). We used 4 M K 2 CO 3 to adjust the pH of the solution to strongly basic, and 5 mL of triple distilled water to promote dispersion of the sample in the pretreatment solvent and to increase the recovery rate.…”

“…Conventional analysis methods for clenbuterol and ractopamine were used to determine the optimal assay conditions for mass spectrometry. Since ions at m/z 203 and 259 have been used in published literature regarding clenbuterol, the collision energy shown in Table 2 was applied to the product ion to obtain ions at these m/z ratios ( Blanca et al ., 2005 ; Cho et al , 2013 ; Suo et al ., 2013 ). For ractopamine, Blanca et al (2005) and Cho et al .…”

“…To detect zilpaterol, Blanca et al . (2005) used m/z 244 and 202 ions, and Suo et al . (2013) used m/z 244 and 185 ions.…”

“…In the present study, ions at m/z 244 and 185, which showed the highest sensitivity upon application of collision energy, were monitored as shown in Table 2 . While the previous studies used ractopamine-d 5 , cimaterol-d 7 , and clenbuterol-d 9 as internal standards ( Blanca et al ., 2005 ; Mauro et al ., 2014 ; Suo et al , 2013 ), zilpaterol-d 7 was used as an internal standard for zilpaterol to improve efficiency and reproducibility in the present study.…”

“…Recently, liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been commonly used since it can quantitatively and qualitatively analyze a substance based on the unique characteristics of mass and fragment ions created by an electrical current ( Juan et al ., 2010 ; Li et al ., 2010 ; Shao et al , 2009 ). Previous studies that have simultaneously analyzed clenbuterol, ractopamine, and zilpaterol by LC/MS/MS were limited in scope to samples from the urine, kidney, liver, and feed ( Blanca et al ., 2005 ; Suo et al ., 2013 ; Williams et al ., 2004 ).…”