Page 339 - CRFTApplication Compendium_090613

Figure 1: Comparison of 1.9 µm Hypersil GOLD stationary phases for the UHPLC separation of 14 illicit drugs. A) Hypersil GOLD aQ,
Method A was applied; B) Hypersil GOLD, Method B was applied; C) Hypersil GOLD PFP, Method C was applied. See Appendix A
for methods details.
Figure 2: UHPLC/MS chromatograms of the 14 illicit drugs with acidic solvent modifiers. A) 0.02%TFA (Method D); B) 0.06% acetic
acid (Method E). See Appendix A for methods details.
6. Calibration Curve and Sensitivity
Calibration curves for the drug
standards were constructed over the
concentration range listed in Table 1
with 10 calibration levels (Figure 5).
Each calibration level was injected
three times and the mean area
responses were plotted against the
concentrations. Correlation coefficients
with R2 = 0.995 or better were
achieved for all illicit drug compounds.
The limit of quantitation (LOQ)
and the limit of detection (LOD) of
the drug compounds were determined
based on the calibration curve of
signal-to-noise ratio versus concentra-
tion and the definitions of LOQ and
LOD using s/n = 10 and 3, respectively.
LOQs for all drugs were in the range
of 0.96-300 ng/mL, while LODs were
from 0.29 to 90.0 ng/mL (Table 1). The
outstanding sensitivity by this method
was highlighted by the achievement
of picogram level quantitation for 10
illicit drugs with 1 µL sample injection.
LOQ LOD Linear Range
Analyte (ng/mL) (ng/mL) (ng/mL)
ephedrine 1.21 0.36 1.3-2000
pseudoephedrine 1.25 0.38 1.3-1670
amphetamine 1.78 0.53 1.3-1670
methamphetamine 0.96 0.29 1.3-1670
3,4-MDMA 1.09 0.33 1.3-1670
hydrocodone 6.80 2.04 4.1-10000
oxycodone 3.48 1.04 3.3-10000
clonazepam 7.39 2.22 3.3-3000
cocaine 1.17 0.35 0.3-1000
noscapine 3.79 1.14 0.7-10000
cannabidiol 300 90.0 274-44400
cannabinol 251 75.4 123-20000
THC 191 57.4 68.5-11100
Table 1: LOQ and LOD of the thirteen drug
compounds with 1 µL sample injection.