Simultaneous determination of antiviral drugs in chicken tissues by ultra high performance liquid chromatography with tandem mass spectrometry.

An ultra high performance liquid chromatography with tandem mass spectrometry method was established for the rapid and simultaneous analysis of seven antiviral drugs, amantadine, rimantadine, memantine, moroxydine, imiquimod, oseltamivir, and acyclovir, in chicken liver, muscle, and egg. Homogenized samples were extracted with trichloroacetic acid and acetonitrile solutions and then purified by cation-exchange solid-phase extraction. The target drugs were analyzed by liquid chromatography with a UPLC BEH Amide column (2.1 mm × 100 mm, 1.7 µm) coupled with a tandem mass spectrometer operating in the positive multiple-reaction mode. A perfectly linear relationship was obtained within the concentration ranges of 0.5-20 µg/L for acyclovir and 0.1-10 µg/L for the other six antiviral drugs. The average recoveries of the seven antiviral drugs using four addition levels in chicken liver, muscle, and eggs were 82.67-90.10, 82.30-92.27, and 81.98-93.77%, respectively, and the acceptable coefficients of variation were 5.18-9.88, 4.84-11.2, and 42.8-9.95%, respectively. The detection limits and detection capabilities of the analysis method for the seven antiviral drugs were in the ranges of 0.04-0.64 and 0.11-0.78 µg/kg, respectively. Additionally, an inter-laboratory study among five laboratories further validated the method.

[Multi-residue determination of five antiviral drugs in chicken tissues by liquid chromatography-electrospray ionization tandem mass spectrometry].

A method of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the simultaneous determination of five antiviral drug residues, amantadine, rimantadine, memantine, moroxydine and imiquimod in chicken tissues was developed. The compounds were extracted from the samples with trichloroacetic acid solution and acetonitrile, and then cleaned-up by strong cation exchange (SCX) solid phase extraction cartridges. The analytes were separated on a Xamide column (100 mm x 2.1 mm, 5 microm) and determined qualitatively and quantitatively with tandem mass spectrometry using positive polarity mode under multi-reaction monitoring (MRM) scan type. The limits of detection and the limits of quantification were 0.06 - 0.30 microg/kg and 0.2 - 1.0 microg/kg, respectively. The average recoveries of the five drugs were 72.3% - 94.2% in chicken muscle and 70.8% - 92.7% in chicken livers. The relative standard deviations (RSDs) in chicken muscle and livers were 3.5% -11.3% and 5.3% -12.6%, respectively. The method is selective without interference and suitable for the determination and confirmation of the five antiviral drugs in chicken muscle and livers.

[Determination of glufosinate residue in tea by liquid chromatography-tandem mass spectrometry coupled with precolumn derivatization].

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of glufosinate (GLUF) residue in tea. The GLUF was extracted with water for 30 min under ultrasonication, and cleaned-up using a C18 solid phase extraction cartridge, then derived using fluorenylmethylchloroformate (FMOC-Cl) in borate buffer for 2 h. The separation was performed on a Kinetex C18 column with the mobile phases of acetonitrile and 5 mmol/L ammonium acetate aqueous solution (containing 0.2% (v/v) formic acid) in a gradient elution mode. The identification and quantification of the GLUF were carried out by MS/MS in negative electrospray ionization (ESI(-)) and multiple reaction monitoring (MRM) mode, the quantification analysis was performed by external standard method. The calibration curve showed good linearity in the range of 2.5 - 50.0 microg/L with the correlation coefficient r2 > 0.999. The limit of quantification (LOQ) was 0.10 mg/kg. The average recoveries of GLUF spiked at 0.10, 0.50 and 1.00 mg/kg levels in tea were between 61.6% and 81.4%, and the relative standard deviations (RSDs) were between 3.2% and 8.4%. The method is simple, rapid, sensitive, accurate and suitable for the confirmation and quantification of GLUF in tea.