METHAMPHETAMINE . . .on Wipes by Liquid-Liquid Extraction: METHOD 9106, Issue 1, dated 17 October 2011 - Page 14 of 31
Table 5. Limit of detection (LOD), method detection limit (MDL), and sample storage stability on cotton gauze. (1) Estimated LOD(3)
Compound
Int. std.(2)
Estimated MDL(4)
Scan Mode SIM Mode Scan Mode (µg/sample) (µg/sample) (µg/sample)
Storage Stability(5)
SIM Mode 30 days 4 °C (µg/sample)
7 days 22 °C
(D)-Amphetamine
D11-Amp D14-Met
0.07 0.06
0.05 0.06
0.04 0.03
0.02 0.03
100.5 99.7
94.5 87.9
Caffeine
D11-Amp D14-Met
1 1
0.2 0.2
0.4 (6) 0.4 (6))
0.02 0.03
99.3 98.5
98.8 91.9
(L)-Ephedrine
D11-Amp D14-Met
0.09 0.08
0.1 0.09
0.02 0.01
0.01 0.06
95.6 94.8
97.2 90.5
MDEA
N-PAmp
0.05
0.07
0.1
0.02
98.9
102.1
MDMA
D11-Amp D14-Met
0.05 0.05
0.06 0.07
0.04 0.03
0.02 0.02
99.7 98.9
111.1 103.2
(D)-Methamphetamine
D11-Amp D14-Met
0.07 0.05
0.05 0.05
0.03 0.03
0.02 0.02
98.7 98.0
100.6 93.5
Phencyclidine
D11-Amp D14-Met
0.3 0.3
0.06 0.07
0.03 0.03
0.02 0.02
103.7 102.9
105.2 97.7
Phentermine
D11-Amp D14-Met
0.06 0.05 0.06 0.2 0.2 0.08 0.07 0.06
0.05 0.05 0.05
0.02 0.02 0.01 0.1 (9) 0.2 (10) 0.03 0.05 0.05
0.02 0.02
102.0 101.1
101.5 94.3
(8)
94.3 93.6 100.4 99.6 -
92.7 86.2 97.9 91.1 -
(±)-Norephedrine(7) Pseudoephedrine
D11-Amp D14-Met D11-Amp D14-Met NMPhen
(8)
0.07 0.09 0.09
(8)
0.02 0.03 0.02
(1) Backup Data Report [1]. (2) Internal standards: D11-Amp = Amphetamine-D11, D14-Met = Methamphetamine-D14, NMPhen = N-Methyl phenethylamine, N-PAmp = N-Propyl amphetamine. (3) LODs vary according to individual GC columns, instrument conditions and cleanliness, media interferences, and internal standards used. The lowest calibration standard for these determinations was 0.05 μg/sample. Lower LODs are achievable with lower concentration calibration standards and operation of the mass spectrometer in the SIM mode. LODs were calculated on liquid standards using the procedure of Burkart [8]. (4) MDLs are provided as an alternate expression of sensitivity. These MDLs are calculated as the standard deviation of six replicates on spiked media analyzed at the 0.1 μg/sample level (except as noted) times the Student’s t value for 6 replicates (3.365). (Normally 7 replicates are used.) (5) Cotton gauze samples were spiked at 3 μg/sample per analyte. Six samples were analyzed immediately after preparation. Six samples were stored at room temperature (about 22 °C) for 7 days and then analyzed. Eighteen samples were stored at +4 °C (±2 °C). Of the 18 samples stored at +4 °C, six each were analyzed at 7 and 21 days and three each were analyzed at 14 and 30 days. (Backup Data Report [1].) Apparent recoveries vary according to internal standard used. (6) The 0.3 μg/sample level was undetectable in the scan mode. MDLs were calculated from the 1 μg/sample level. (7) (±)-Norephedrine = (±)-phenylpropanolamine. (8) (±)-Norephedrine was not evaluated in the SIM mode due to breakdown of derivative with room temperature storage for one week. (9) MDL calculated from the 0.3 μg/sample level. (Recoveries were >120% at the 0.1 μg/sample level.) (10) MDL calculated from the 1 μg/sample level. (Recoveries were >120% at the 0.1 and 0.3 μg/sample levels.)
Method rev. 1.1.1
NIOSH Manual of Analytical Methods (NMAM), Fifth Edition
