Page 75 - Clinical-Medical Solution for Clinical Chemistry

Quantitative Multi Target Screening (MTS) using liquid
chromatography-tandem mass spectrometry with MS/MS library
based identi cation for forensic toxicology

Library hits

A MTS procedure for clinical and forensic toxicology screening was developed for a single LC/MS/MS method following
a QuEChERS extraction of whole blood. This approach results in robust quantitation using MRM data and enables a
higher degree of con dence in compound identi cation as shown in Table 2.

Table 2. Library search results for a panel of drugs spiked into whole blood and extracted by QuEChERS from three QC levels (low, medium and
high QC’s correspond to 20, 100, 500 ug/L). Most compounds can be identi ed as the rst hit in a spectral based library match (5 compounds
are identi ed as the second candidate in the library; for 4 compounds the hit was not identi ed as either the rst or second candidate).
Quality control level Quality control level
RT Low Medium High RT Low Medium High
Compound Compound
(min) Library Hit (min) Library Hit
Merged CE spectrum Merged CE spectrum
Paracetamol 3.02 2 1 1 2-(2-amino-5-bromobenzoyl)pyridine 7.43 1 1 1
Levetiracetam 3.49 1 1 1 Dextropropoxyphene 7.44 1 1 1
Theophylline 3.67 1 1 1 Desalkyl urazepam 7.60 - 1 1
Scopolamine 4.05 1 1 1 Zolpidem 7.75 1 1 1
Felbamate 4.51 1 2 1 Hydroxyzine 7.80 1 1 1
Lamotrigine 4.81 2 2 1 Hydroxyalprazolam 7.82 1 1 1
Tramadol 5.18 1 1 1 4-hydroxymidazolam 7.87 1 1 1
10-hydroxycarbamazepine 5.24 1 1 1 Chlordiazepoxide 7.89 1 1 1
7-aminonitrazepam 5.33 1 1 1 1-hydroxymidazolam 8.07 1 1 1
7-aminoclonazepam 5.36 1 1 1 Nordiazepam 8.07 - 1 1
Ketamine 5.67 1 1 1 Clobazam 8.09 1 1 1
Niaprazine 5.77 1 1 1 Flunitrazepam 8.20 1 1 1
Norbuprenorphine 6.08 1 1 1 Lormetazepam 8.21 1 1 1
3-Hydroxybromazepam 6.15 1 1 1 Estazolam 8.32 1 1 1
Doxylamine 6.36 1 1 1 Temazepam 8.37 1 1 1
LSD 6.45 1 1 1 Triazolam 8.38 1 1 1
Diphenhydramine 6.78 1 - 1 Ethyl lo azepate 8.44 1 1 1
Carbamazepine 6.90 1 1 1 Alprazolam 8.58 1 1 1
Zopiclone 6.99 1 1 1 Midazolam 9.01 2 1 1
Desmethyl unitrazepam 7.09 1 1 1 Diazepam 9.05 1 1 1
N-desmethylclobazam 7.19 1 1 1 11-OH-THC 9.23 1 1 1
Lorazepam 7.20 1 1 1 THC 9.37 1 1 1
3-hydroxy- unitrazepam 7.36 1 1 1 Clotiazepam 9.49 1 1 1
Oxazepam 7.37 - 1 1 THC-COOH 9.51 1 1 1
Flurazepam 7.37 1 1 1 Tetrazepam 9.60 1 1 1
Clonazepam 7.40 1 1 1 Cannabinol 9.94 1 1 1
Nitrazepam 7.41 1 1 1 Loprazolam 10.09 1 1 1

7