Page:NIOSH Manual of Analytical Methods - 9111.pdf/9

METHAMPHETAMINE on Wipes by LC/MS : METHOD 9111, Issue 1, dated 17 October 2011 - Page 9 of 12

Table 2. Suggested Mass Spectrometer SIM Conditions Ionization Mode: Polarity: Fragmentator:

API-ES (Atmospheric Pressure Ionization –Electrospray) Positive 100

Gain: Actual Dwell: SIM ions:

3.0 EMV 294 119 Methamphetamine confirmation ion 150 Quantitation ion for methamphetamine 164 Ion for methamphetamine-D14 Spray Chamber: (Optimize for the particular instrument in use.) Gas Temperature: 200 °C Drying Gas: 12.0 L/min Nebulizer Pressure 50 psig Note 1: Methamphetamine and the internal standard essentially co-elute. Monitor m/z ions 119 and 150 for methamphetamine quantitation and 164 for methamphetamine-D14. Note 2: These instrumental conditions are suggestions and should be optimized by the analyst. Each mass spectrometer will be different and the acid concentration and composition will alter the conditions. Furthermore there is the possibility of using MS/MS for these analyses if the laboratory is equipped with that instrumentation. This tandem MS could add specificity and sensitivity to the method but was not part of this method development.

Table 3. Suggested spiking schedule for calibration standards Volume (µL) of Methamphetamine Spiking Solution Spiked on Media Standard

200 µg/mL solution

20 µg/mL solution

Internal Standard Spike (µL)

Desorption Solution (mL)

Final Concentration (µg/ sample)

1

500

50

30

100

2

100

50

30

20

3

25

50

30

5

4

5

50

30

1

5

25

50

30

0.5

6

5

50

30

0.1

7

2.5

50

30

0.05

8

1.2

50

30

0.024

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

Method rev. 1.1.1