Coupling device for desorption of drugs from solid-phase extraction-pipette tips and on-line gas chromatographic analysis

• Published in: Journal of Chromatography A Vol. 858; no. 1; pp. 117 - 122
• Main Authors: van Hout, M.W.J, de Zeeuw, R.A, de Jong, G.J
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 08.10.1999; Elsevier
• Subjects: Analysis; Analytical chemistry; Benzodiazepines; Biological and medical sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, Gas - methods; Diazepam; Diazepam - isolation & purification; Exact sciences and technology; Gas chromatographic methods; General pharmacology; Lidocaine; Lidocaine - isolation & purification; Medical sciences; Pharmacology. Drug treatments; Injection methods; Interfaces, solid-phase extraction-pipette tips–programmed-temperature vaporiser; Instrumentation; Programmed-temperature vaporiser; Lidocaine; Diazepam; Benzodiazepines; Solid phase extraction; On line; Aminoamide; Coupled method; Psychotropic; Hypnotic; Anticonvulsant; Flame ionization detector; Injection; Antiarrhythmic agent; Local anesthetic; Programmed temperature; Gas chromatography; Sample preparation; Tranquillizer; Microequipment; Benzodiazepine derivatives; Miniaturization; Interface
• ISSN: 0021-9673
• DOI: 10.1016/S0021-9673(99)00806-7

Solid-phase extraction-pipette tips were used for micro solid-phase extraction of lidocaine and diazepam. Off-line desorption was done after in-vial collection for reference purposes, whereas with on-line desorption the eluate was directly introduced in the gas chromatograph. With both methods the total eluate (100 μl) was introduced into the GC system, which was equipped with a programmed-temperature vaporiser (PTV) for large volume injection. For on-line desorption a laboratory-made coupling device was developed to connect the pipette tips with the injector of the PTV. The coupling device was applied successfully since no leakage occurred at the connection of the coupling device and the pipette tip. No significant differences in recovery of lidocaine and diazepam and in presence of impurities were observed between chromatograms obtained with either off-line or on-line desorption. Preliminary experiments with standard solutions showed recoveries of about 75% for a concentration level of 1 μg/ml. The system seems particularly suitable for high-throughput analysis.