353 / 658
-ETHOD 0ERFORMANCE
Sample preparation for urine analysis of benzodiazepines
was previously done with solid phase extraction (SPE).
Here we tested a simple urine dilution strategy. The
absolute recovery of deuterated benzodiazepine internal
standards was tested with several lots of human urine.
It was determined that the absolute recoveries of the
internal standards ranged from 83.0% to 100.5% at
100 ng/mL from all lots of urine tested (data not shown).
This method was linear from 5 to 1000 ng/mL for all
14 benzodiazepines with an accuracy of 85.4%-106.0%.
Inter- (n=15) and intra-batch (n=5) coefficients of
variation (CV) at two different concentration levels ranged
from 0.5% to 11.7%. The method has a lower limit of
quantitation (LLOQ) of 5 ng/mL for all 14 benzodiazepines
tested. The method performance is summarized in Table 1.
Figure 10 shows the extracted ion chromatograms (XICs)
with 3 ppm mass isolation window of all 14 benzodiaz-
epines at their LLOQ (5 ng/mL).
1# LEVEL
NG M,
1# LEVEL
NG M,
Name
m/z
% Precision % Accuracy
% Precision
% Accuracy
,INEAR 2ANGE ,,/1
NG M,
NG M,
7-Aminonitrazepam
252.1131
2.9
88.7
2.9
106.0
5 - 1000
5
Nordiazepam
271.0633
5.7
89.6
2.9
100.9
5 - 1000
5
7-Aminoflunitrazepam
284.1194
3.4
91.2
4.0
100.9
5 - 1000
5
Diazepam
285.0789
8.8
96.0
2.6
99.7
5 - 1000
5
7-Aminoclonazepam
286.0742
2.0
89.1
2.1
99.4
5 - 1000
5
Oxazepam
287.0582
5.0
85.6
3.5
98.4
5 - 1000
5
Desalkylflurazepam
289.0539
5.5
88.5
2.9
98.6
5 - 1000
5
Temazepam
301.0738
3.4
89.1
2.7
97.6
5 - 1000
5
Alprazolam
309.0902
3.1
90.0
3.2
101.5
5 - 1000
5
Lorazepam
321.0192
7.6
85.4
3.4
95.3
5 - 1000
5
α
-Hydroxyalprazolam
325.0851
3.0
87.0
1.8
97.3
5 - 1000
5
Midazolam
326.0855
3.6
91.3
2.6
101.2
5 - 1000
5
2-Hydroxyethylflurazepam
333.0801
3.7
89.0
2.5
99.7
5 - 1000
5
α
-Hydroxytriazolam
359.0461
5.9
86.9
2.8
97.5
5 - 1000
5
Table 1. Method performance for 14 benzodiazepines in urine