Comparative study of liquid-liquid extraction and solid-phase extraction methods for the separation of sufentanil from plasma before gas chromatographic-mass spectrometric analysis
C. Dufresne et al., Comparative study of liquid-liquid extraction and solid-phase extraction methods for the separation of sufentanil from plasma before gas chromatographic-mass spectrometric analysis, CLIN CHEM, 47(3), 2001, pp. 600-602