| Summary: | 博士 === 中原大學 === 化學研究所 === 105 === This project focuses on two major research topics which concern the development of sample preparation method for veterinary drug residues with liquid chromatography–mass spectrometry. One of the topics was a novel online eluent switching for one single anion exchange column to perform the online extraction, separation and analysis of nine non–steroidal anti–inflammatory drugs in pig serum. The successful extraction and separation of nine non–steroidal anti–inflammatory drugs(carprofen, diclofenac, flunixin, ibuprofen, ketoprofen, meclofenamic acid, mefenamic acid, niflumic acid, and tolfenamic acid)were through their different degree of dissociation by their different pKa values at different pHs plus different intermolecular π–π interactions and dipole–dipole forces with the anion–exchanger on the stationary phase. The limit of detection of the analysis was in the range of 0.2–2.5 ng/mL. The intraday and interday precision were in the range of 2.1–14.5% and 2.8–6.5%, respectively. The analysis accuracy were in the range of 87.2–99.8%. These data show excellent analytical sensitivity, accuracy, and precision. Real pig serum sample analysis showed a greatest concentraction of 3480 ± 36 ng/mL and 431 ± 13 ng/mL for flunixin and tolfenamic acid, respectively, after one hour injection of one flunixin and tolfenamic acid dosage. Both residues were reduced to about 20 ng/mL at the time of 24 h later after injection and were less than the regulated maximum allowed residue level.
The second topic was the development of a two dimensional chromatography–mass spectrometric system by coupling a cation–exchange solid phase microextraction column to a reversed–phase liquid chromatography column for extracting, separating, and analyzing five ionophore coccidiostats in eggs. The first chromatographic dimension performs the online solid–phase extraction by the cation–exchange mechanism between sodium bearing coccidiostats cations and the cation–exchamger stationary phase. The second chromatographic dimension was for the separation of five ionophore coccidiostats(lasalocid, maduramicin, monensin, narasin, and salinomycin)by the C18 reversed–phase column. The limit of detection of the mass spectrometry was in the range of 0.15–0.19 ng/mL. The intraday and interday precision were in the range of 3.2–9.7% and 3.0–4.9%, respectively. The analysis accuracy were in the range of 90.0–99.6%. These data show excellent analytical sensitivity, accuracy, and precision. The real egg samples were collected from hens fed either with or without maduramicin containing feed for one week. The results indicated a greatest maduramicin concentration of 100.1 ng/mL at the second day of drug withdrawal. After seven days of drug withdrawal, the maduramicin residue concentration was 12.2 ng/mL which disobeys the regulated maximum allowed residue level of not detection.
|
|---|
