SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A68
MULTI TARGET SCREENING (MTS) FOR 300 DRUGS USING A LINEAR ION TRAP MASS
SPECTROMETER AND LIBRARY SEARCHING
Wolfgang Weinmann', I, Claudia A. MUller l , Barbora Maralikova I, Andre Schreiber 2 , Merja Gergov 3 ,
[Institute of Forensic Medicine, University Hospital, AlbertstraBe 9, D 79104 Freiburg (Germany), Phone:
++497612036828, Fax: ++49 7612036858, Email: Weinmann@ukl.uni-freiburg.de, 2Applied
Biosystems; Frankfurter StraBe 129B; 64293 Darmstadt (Germany), 3University of Helsinki; Department of
Forensic Medicine; P.P, Box 40; 00014 Helsinki (Finland)
A Multi Target Screening (MTS) procedure for drugs in blood and urine for toxicological analysis has been
developed for the rapid detection and identification of tranquilizers (benzodiazepines), hypnotics, drugs of
abuse (opiates, cocaine, amphetamines, cannabinoids), antidepressants, neuroleptics, and cardiac drugs
using LC/MSIMS with a linear ion trap-based tandem-mass spectrometer. In comparison to common
GC/MS or LC/MSIMS methods used for target analysis, the combination of Multiple Reaction Monitoring
(MRM) and Enhanced Product Ion (EPI) scan in an Information Dependent Acquisition (IDA) experiment
with library searching offers both sensitive target analyte detection and subsequent identification by a mass
spectrometric database in a single LC/MS/MS run. Liquid-Liquid Extraction or Solid Phase Extraction has
been used for sample clean up. Reversed-phase gradient LC with run-time of 30 minutes and MS/MS
analysis have been performed in MRM using a Q TRApTM LC/MSIMS system with a TurboIonSpray®
source. Similar to previous work ofGergov et at. [1] and in contrast to a method presented by Marquet et
at. [2] , who used scan-mode for the survey scan - in the presented method 300 MRM-transitions have
been monitored with short dwell times of 5 milliseconds each as survey scan of the IDA experiment. In
case of a positive detection of an MRM transition, an EPI scan of the precursor ion was triggered as
dependent scan, yielding product ion mass spectra at three pre-selected collision energies with the high
sensitivity of the linear ion trap. Obtained EPI spectra were then searched against a newly created product
ion spectral library, Fit, Reverse fit and Purity fit values are given as results in a library search hit list. A
ready-to-use acquisition method and mass spectral library with Enhanced Product Ion spectra of 300
compounds is presented. The developed method was successfully applied to samples of forensic cases,
Dynamic exclusion of detected MRM transitions was used to detect co-eluting compounds. This was
especially important for intoxication cases, where concentrations are usually 10 to more than 100 times
higher than normal therapeutic concentrations. Examples of library searching with identification based on
fit and purity fit values are given for amitriptyline (at CE of 35eV) and dibenzepine (CE of 50eV) and
others. Purity fit values above 0.9 were obtained for all cases. The results were confirmed by established
chromatographic screening methods, The developed method showed high sensitivity and selectivity. A
further advantage of this method in contrast to the published method of Gergov at al. [1] is that the sample
has to be injected only once, so less time is needed for the analysis. Conclusions: The developed method is
useful for the rapid detection and identification of 300 pre-selected target compounds in blood extracts of
forensic and clinical cases using ESI or APCI. After introduction of retention time windows ("periods")
with each containing up to 300 compounds the number of target analytes can even be increased to more
than 1000 compounds per analysis.
l. Gergov M, Ojanpera I, Vuori E. Simultaneous screening for 238 drugs in blood by liquid
chromatography-ion spray tandem mass spectrometry with multiple-reaction monitoring. J
Chromatogr B 2003,795, 41 - 53.
2. Marquet P, Saint-Marcoux F, Gamble TN, Leblanc J C. Comparison of a preliminary procedure
for the general unknown screening of drug and toxic compounds using a quadrupole linear iontrap
mass spectrometer with a liquid chromatography - mass spectrometry reference technique. J
Chromatogr B 2003,798,9 18
Keywords: Multi target screening, LC-MS/MS library, Information dependent acquisition
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