247 / 658
3
Results and Discussion
Matrix Effects
Matrix effects were assessed with the nine individual human
urine samples. Absolute recovery was determined by
comparing the signals of unlabeled drugs in urine and
water samples. Relative recovery was determined by
comparing the analyte/IS ratio in urine and water samples.
The recovery/matrix effects results are summarized in
Table 2. All 43 drugs had almost full absolute recovery
(between 80% and 120%), except morphine for which
the matrix effect was compensated by the use of its
internal standard, morphine-d3. The observed precision
from the nine individual human urine samples was below
15% for most of the 43 drugs.
Average Absolute
Recovery (%, n=9)
CV
(%, n=9)
Average Relative
Recovery (%, n=9)
CV
(%, n=9)
Drug
20
ng/mL
200
ng/mL
20
ng/mL
200
ng/mL
20
ng/mL
200
ng/mL
20
ng/mL
200
ng/mL
6-MAM
86.7
92.3
16.2
12.2
95.1
100.2
5.6
5.7
7-Amino-clonazepam
96.4
108.4
11.0
11.6
90.3
103.7
6.1
5.8
7-Amino-flunitrazepam
86.8
90.5
11.4
8.4
97.1
102.1
6.3
5.1
7-Aminonitrazepam
86.0
85.5
12.3
9.6
80.6
81.9
9.9
8.2
a
-Hydroxy-alprazolam
87.4
87.4
12.9
6.7
99.4
96.2
10.4
4.1
Alprazolam
94.0
89.1
26.0
16.6
95.1
84.8
22.9
13.9
Amphetamine
109.5
112.3
11.8
8.0
112.4
110.8
16.7
3.8
Benzoylecgonine
82.7
85.7
13.0
12.7
98.7
100.9
4.6
3.6
Benzylpiperazine
87.3
85.4
10.0
7.2
100.4
100.6
8.7
7.5
Buprenorphine
108.4
96.9
15.0
6.2
118.1
97.2
14.6
5.4
Carisprodol
88.0
96.3
13.1
11.0
100.5
105.8
13.6
8.4
Clonazepam
100.7
98.4
9.5
6.9
103.4
94.4
13.6
9.5
Cocaine
93.6
93.5
7.4
8.2
95.5
92.2
5.3
5.0
Codeine
93.9
98.9
8.6
8.2
99.3
98.0
3.3
7.2
Diazepam
98.0
96.6
14.0
9.1
106.5
96.7
11.7
6.5
EDDP
103.8
99.2
6.8
2.9
106.8
95.0
13.7
6.2
Fentanyl
98.6
100.9
4.1
2.8
101.4
96.7
10.7
5.8
Flunitrazepam
85.7
86.9
18.8
14.7
87.1
82.9
14.6
12.1
Flurazepam
97.5
103.1
4.2
3.9
100.2
98.8
11.7
5.8
Hydrocodone
91.5
96.4
15.1
13.5
95.2
97.9
7.8
9.6
Hydromorphone
91.2
94.5
11.0
10.4
104.6
110.8
7.2
5.4
Lorazepam
105.7
90.5
16.5
6.0
120.7
99.7
17.2
5.7
MDA
96.6
105.8
16.1
9.6
100.6
107.9
8.7
6.4
MDEA
95.6
94.0
11.8
10.1
99.0
82.8
9.7
10.6
MDMA
92.3
94.3
9.3
7.8
106.1
102.4
2.4
4.1
Meperidine
88.4
88.4
9.8
9.9
96.2
88.5
7.4
7.8
Methadone
101.6
103.2
3.2
3.4
111.1
103.6
8.9
5.4
Methamphetamine
94.6
86.2
12.3
11.1
105.5
94.1
8.4
5.6
Midazolam
98.4
97.4
9.5
5.5
107.1
97.6
6.0
3.5
Morphine
48.1
53.8
6.0
8.2
90.5
98.4
6.9
5.4
Naloxone
124.2
129.4
17.9
16.1
116.1
123.5
9.9
7.7
Naltrexone
96.1
100.2
12.6
10.9
100.3
101.9
5.2
6.1
Norbuprenorphine
76.9
104.6
19.4
14.2
78.9
99.9
20.4
11.6
Nordiazepam
102.8
107.1
21.3
7.3
106.3
94.2
19.8
7.5
Norfentanyl
89.5
92.2
11.4
8.2
103.2
100.1
12.4
4.5
Normeperidine
81.7
92.0
11.9
11.6
83.1
87.7
7.8
8.4
Oxazepam
93.8
91.3
10.8
5.1
113.4
102.1
6.8
4.7
Oxycodone
80.4
84.7
8.8
10.9
97.0
100.1
9.7
6.1
Oxymorphone
107.0
101.4
15.2
12.9
100.1
97.0
8.2
9.0
PCP
100.8
100.5
4.2
4.3
110.3
100.9
8.8
5.1
Propoxyphene
101.3
103.8
6.8
5.8
111.2
104.1
15.3
4.4
Temazepam
95.3
102.2
14.2
7.1
97.3
97.7
12.3
4.6
Tramadol
77.8
84.8
14.1
12.9
78.9
80.8
10.1
10.4
Table 2. Summary of matrix effects