248 / 658
4
accuracy ranged between 89.9% and 118.4%, and
precision ranged between 3.6% and 19.5%. The method
was linear to 1000 ng/mL for all the drugs. Figure 1 shows
the calibration curves of six typical pain management
drugs in human urine.
Lower Limit of Quantitation, Linear Range,
Accuracy, and Precision
The LLOQ of these 43 drugs and other aspects of analytical
performances of this method are summarized in Table 3.
Linear fit with 1/X weighting was used for calibration
curves of all the 43 drugs. The LLOQ for these 43 drugs
was determined to be between 2 and 20 ng/mL except for
tramadol, which was 50 ng/mL. At the LLOQ, the
Table 3. Lower limit of quantitation, linear range, accuracy, and precision
Drug
Retention
Time
(min)
LLOQ
(ng/mL)
Accuracy at
LLOQ
(%, n=4)
CV at LLOQ
(%, n=4)
Linear Range
(ng/mL)
R
2
Precision
20 ng/mL
(%, n=6)
Precision
200 ng/mL
(%, n=6)
6-MAM
2.97
2
95.0
14.6
2–1000
0.9955
5.8
2.8
7-Amino-clonazepam
2.76
5
95.1
10.1
5–1000
0.9988
3.4
4.0
7-Amino-flunitrazepam
3.31
5
101.0
13.7
5–1000
0.9980
5.3
4.0
7-Aminonitrazepam
2.51
2
102.0
9.6
2–1000
0.9972
3.7
3.2
a
-Hydroxy-alprazolam
3.87
20
94.0
10.0
20–1000
0.9972
6.9
5.9
Alprazolam
4.11
5
94.1
13.1
5–1000
0.9950
2.7
1.2
Amphetamine
2.97
20
94.9
7.7
20–1000
0.9944
5.4
5.5
Benzoylecgonine
2.99
5
92.3
3.6
5–1000
0.9990
2.7
2.0
Benzylpiperazine
2.70
10
96.0
10.4
10–1000
0.9979
9.5
5.0
Buprenorphine
4.50
20
94.7
17.3
20–1000
0.9976
6.0
6.1
Carisprodol
3.80
10
104.5
11.3
10–1000
0.9903
9.5
6.3
Clonazepam
4.00
20
92.7
7.7
20–1000
0.9954
9.1
6.1
Cocaine
4.23
5
101.2
7.4
5–1000
0.9969
4.0
3.7
Codeine
2.82
10
110.4
18.3
10–1000
0.9978
6.6
3.8
Diazepam
4.24
5
93.0
11.9
5–1000
0.9979
7.0
3.4
EDDP
4.90
10
106.5
3.9
10–1000
0.9944
4.5
2.2
Fentanyl
4.62
2
108.9
3.7
2–1000
0.9975
4.8
1.8
Flunitrazepam
4.12
20
93.7
17.2
20–1000
0.9904
6.4
4.4
Flurazepam
4.57
2
118.4
3.6
2–1000
0.9961
4.9
2.4
Hydrocodone
3.16
2
106.6
9.6
2–1000
0.9988
7.8
2.8
Hydromorphone
2.25
2
89.9
13.2
2–1000
0.9979
8.2
3.1
Lorazepam
3.86
20
92.5
17.3
20–1000
0.9943
2.2
9.6
MDA
3.16
10
93.1
6.8
10–1000
0.9974
1.1
3.1
MDEA
3.97
2
104.3
4.5
2–1000
0.9937
7.5
4.4
MDMA
3.61
5
97.3
4.3
5–1000
0.9975
7.6
2.2
Meperidine
4.20
5
101.2
9.6
5–1000
0.9986
5.5
4.6
Methadone
4.95
5
100.3
3.8
5–1000
0.9982
4.2
3.0
Methamphetamine
3.51
5
106.0
5.1
5–1000
0.9979
5.0
4.0
Midazolam
4.48
2
117.1
12.7
2–1000
0.9983
7.0
4.3
Morphine
1.71
5
93.0
13.6
5–1000
0.9990
5.0
3.3
Naloxone
2.86
10
102.3
10.9
10–1000
0.9944
3.3
2.9
Naltrexone
3.11
5
101.9
7.0
5–1000
0.9985
5.1
1.6
Norbuprenorphine
4.13
20
101.4
14.4
20–1000
0.9955
3.9
8.4
Nordiazepam
4.06
10
97.1
19.5
10–1000
0.9948
8.4
3.8
Norfentanyl
3.68
10
102.5
6.3
10–1000
0.9985
7.1
2.3
Normeperidine
4.00
2
116.2
11.2
2–1000
0.9982
7.3
4.2
Oxazepam
3.88
20
108.0
15.0
20–1000
0.9970
10.9
6.4
Oxycodone
3.03
5
91.9
11.7
5–1000
0.9982
2.6
2.3
Oxymorphone
2.01
2
93.3
9.5
2–1000
0.9946
10.0
2.6
PCP
4.83
2
100.9
4.0
2–1000
0.9981
7.8
3.0
Propoxyphene
4.70
10
113.6
4.1
10–1000
0.9978
7.3
5.2
Temazepam
4.05
5
104.6
16.9
5–1000
0.9981
5.6
2.2
Tramadol
4.04
50
98.8
2.5
50–1000
0.9970
NA
2.5