Development and validation of an LC-MS/MS confirmatory method for residue analysis of cyproheptadine in urine of food-producing animals.

The possible off-label and illegal use of cyproheptadine (CYP) as an appetite stimulant for food-producing animals creates the need for methods capable of detecting it. A high-performance liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed to identify CYP in bovine urine, according to Commission Decision 2002/657/EC. Two multiple reaction monitoring (MRM) transitions for each analyte were monitored: 288.1/96.1 and 288.1/191.2 for CYP and 282.1/167.2 and 282.1/116.3 for diphenylpyraline hydrochloride (DPP), which was used as an internal standard. The solid phase extraction technique without a liquid-liquid step gives good results in urine samples from treated animals. The analytical method was successfully validated for linearity (0.15-10 ng/mL), with intraday precision of 9.4%, interday precision of 20.4%, and accuracy of 96.7%. The decision limit (CCalpha) and detection capability (CCbeta) were 0.48 and 0.82 ng/mL, respectively.