Assessment of Tear Concentrations on Therapeutic Drug Monitoring. III. Determination of Theophylline in Tears by Gas Chromatography/Mass Spectrometry with Electron Ionization Mode

2003 ◽  
Vol 18 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Masaharu Nakajima ◽  
Shinji Sato ◽  
Susumu Yamato ◽  
Kenji Shimada ◽  
Shuji Kitagawa ◽  
...  
1994 ◽  
Vol 77 (4) ◽  
pp. 917-924 ◽  
Author(s):  
Roger T Wilson ◽  
Joseph M Groneck ◽  
Kathleen P Holland ◽  
A Carolyn Henry

Abstract A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid–liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 CI). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 ± 6.6% for liver tissues across all 3 species and 67.1 ± 3.8% for muscle tissue across all 3 species.


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