Abstract:

This study was conducted to detect and identify the metabolites of clorprenaline in swine urine using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS), and the major metabolic pathways of clorprenaline were proposed. The swines were administered a single dose each of 10 mg/kg b. w. clorprenaline by oral gavage. The urine samples were collected before and after administration. After a simple preparation, the urine samples were analyzed using UPLC/Q-TOF MS. Combined with data processing techniques including extracted ion chromatography (EIC) and mass defect filtering (MDF), two phase Ⅰ and seven phase Ⅱ metabolites were detected in the urine samples collected 0-24 h after administration. The structures of detected metabolites were elucidated by comparing their characteristic product ions with those of the parent clorprenaline. Based on the identified metabolites, the metabolic pathways of clorprenaline included hydroxylation, glucuronidation and sulphate conjugates. Among those detected metabolites, hydroxylated-clorprenaline and its conjugates were responsible for over 60% of the total MS responses, much greater than those of clorprenaline, and were proposed as the primary metabolites in swine urine. This study can provide scientific basis for determining appropriate marker residues of clorprenaline, and facilitate to effectively control clorprenaline residues in animals.

Key words: clorprenaline, metabolites, swine urine, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS)