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A general unknown screening for drugs and toxic compounds in human serum

Sturm, Stefan. A general unknown screening for drugs and toxic compounds in human serum. 2005, Doctoral Thesis, University of Basel, Faculty of Science.

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Official URL: http://edoc.unibas.ch/diss/DissB_7295

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Abstract

Screening for a wide range of drugs and toxic compounds in biological samples is an
important task for forensic and clinical toxicological laboratories. Our object was to
develop a method to detect and identify a wide range of compounds by using HPLCDAD
and LC-MS.
A solid-phase extraction procedure using polymer-based columns was developed for the
HPLC-DAD procedure. The extraction method appeared very universal. Ninteyfour of
100 drugs were extracted with a recovery of more than 50%.
For the LC-MS procedure, the Prospekt solid-phase extraction was chosen for its ability
to be linked to the atmospheric pressure chemical ionisation (APCI) ion source. With this
procedure all of the tested drugs with LC-MS were successfully extracted.
Hundred compounds from a variety of classes were investigated, if they can be identified
and detected at low toxic serum concentration. Limits of detection were determined in
spiked serum samples.
It was found that HPLC-DAD was able to detect 61 out of 100 compounds with our
procedure at low toxic serum concentration. The limit of detection (LOD) for the
majority of the tested drugs (76%) was ≤ 1’000 ng/mL. Drugs and toxic compounds were
detected by comparison of the retention time and UV spectra with references compounds
stored in a library.
The LC-MS instrument was operated in the positive and in the negative mode using datadependent
acquisition. Tandem mass spectrometry (MS-MS) was applied to identify
toxicologically relevant substances in serum. An application program was created in
order to detect automatically the unknown compounds. Drugs and metabolites were
identified on the basis of their relative retention times, pseudo-molecular ions and
fragment ions. A total of more than 400 spectra of more than 350 compounds were
recorded. The corresponding relative retention times were added to the spectra in the
constructed libraries (one for the positive and the other library for the negative mode).
Eightyseven drugs of compounds were identified from serum using on-line solid-phase
extraction with LC-MS-MS. The limit of detection (LOD) for the majority of compounds
(67%) was ≤ 100 ng/mL, ranging from 10 to 4000 ng/mL.
With the presented fully automated data-dependent LC-MS-MS procedure drugs can be
analysed in serum with a high specificity and sensitivity. The LODs were sufficiently low
to detect compounds at low toxic concentrations in serum. The integrated software
drastically reduced the interpretation time. It was demonstrated that with the DDAmediated-
LC-MS-MS screening approach almost all of the drugs detected by the
conventional techniques as well as additional drugs were identified. This technique is
useful for GUS and confirmation analysis in clinical and forensic toxicology. In general,
LOD for compounds are lower with the LC-MS procedure than the HPLC procedure. For
compounds not able to detect with the LC-MS procedure such as analgesics and
barbiturates HPLC-DAD appeared to be the complement method.
Advisors:Hauser, Peter C.
Committee Members:Eberle, Alex N. and Drewe, Jürgen
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Analytische Chemie (Hauser)
UniBasel Contributors:Hauser, Peter C. and Eberle, Alex N. and Drewe, Jürgen
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:7295
Thesis status:Complete
Bibsysno:Link to catalogue
Number of Pages:108
Language:English
Identification Number:
Last Modified:22 Apr 2018 04:30
Deposited On:13 Feb 2009 15:16

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