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methanol, and was run at an isocratic flow rate of 0.5 mL/min. The injection volume was 10 µL. The ion spray voltage was 5000 V and the source temperature was 600 °C with 30 mL/min curtain gas flow. The instrument was operated in multiple reaction monitoring mode (MRM) monitoring the following m/z transitions: nicotine, 163>130 and 163>117; and nicotine-d4, 167>134. A linear regression was plotted of peak area ratio of nicotine to internal standard versus nicotine concentration. A method for quantitation of methamphetamine was validated using an Agilent 6890N Gas Chromatograph coupled to a 5973 Mass Selective Detector per SWGTOX guidelines. Chromatographic separation was performed on a HP-5MS column 30 m x 0.25 mm id x 0.25 mm (Agilent, Santa Clara, CA). The GC/MS was operated in a split mode at a ratio of 6:1, with 1 µL injection volume. The carrier gas was helium at a linear velocity of 35 cm/s. The GC had an oven temperature of 120 °C-200 °C at a rate of 10 °C/min then ramped to 280 °C at a rate of 30 °C/min. The MSD was operated in SIM mode with 58, 64, 91, 96, 134 m/z as the selected ions. Quantification was performed using 58 and 64 m/z as the quantitative ions for methamphetamine and methamphetamine-d11, respectively. The qualitative ions for methamphetamine were 91 and 64 m/z and 91 m/z for methamphetamine-d11. The total run time of 10.67 minutes. A six-point calibration curve was constructed with methamphetamine concentrations of 100, 200, 500, 750, 1000, and 2000 ng/mL with 500 ng/mL of methamphetamine-d11 as internal standard. The calibration curve was matrix-matched and was extracted from water using the method previously described. A linear regression was generated using the peak area ratio counts of methamphetamine and internal standard versus the theoretical calibrator concentrations, and r2 > 0.9981 for all curves. The limit of quantitation was administratively set to 100 ng/mL. Six sets of controls were included with each analytical batch: Limit of Detection QC (100 ng/mL), Low QC (150 ng/mL), Mid QC (600 ng/mL), High QC (1500 ng/mL), a blank, and a double blank. Intraday precision and bias were determined by the largest percent coefficient of variation (% CV) and by the largest percent difference of the five runs (N=5). Carryover was assessed by injecting the lowest quality control (150 ng/mL) following the injection of the high-quality control (1500 ng/mL). (Figure 5). A method for the quantitation of methadone was validated using an Agilent 6890N Gas Chromatograph coupled to a 5973 Mass Selective Detector per SWGTOX guidelines. Chromatographic separation was performed on a HP-5MS column 30 m x 0.25 mm id x 0.25 mm (Agilent, Santa Clara, CA). The GC/MS was operated in a split mode at a ratio of 20:1, with 1 µL injection volume. The carrier gas was helium at a linear velocity of 20 mL/min. The GC had a front inlet temperature of 275 °C. The temperature program began with the oven temperature of 225 °C, and then programmed at a rate of 15 °C/min to 285 °C. The MSD was operated in SIM mode with 72, 223, 294, and 309 m/z as the selected ions for methadone and 78, 226, 303, and 318 m/z for methadone-d9. A seven-point calibration curve ranging from 100-5000 ng/mL of methadone was prepared along with a blank, a double blank control, and controls containing methadone and its internal standard were analyzed. The controls were run in triplicate with Limit of Detection/Quantitation control at 100 ng/mL; a low-control at 150 ng/mL; a mid-control at 1000 ng/mL; and a high-control at 4500 ng/mL. The limit of detection was arbitrarily set to match the limit of quantitation at 100 ng/mL. An internal standard (500 ng/mL methadone-d9) was 8 This resource was prepared by the author(s) using Federal funds provided by the U.S. Department of Justice. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice. added to each calibrator, blank, controls, and sample. The coefficient of determination (r2 ) was 0.9985 for all calibration curves. The bias for all the controls (n=3) for methadone ranged from 5- 15% with coefficient