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|Column||Rxi-5Sil MS 30 m, 0.25 mm ID, 0.25 µm (cat.# 13623)|
|Rtx-200 1.3 m, 0.25 mm ID, 0.25 µm (cat.# 15124)|
|Standard/Sample||Tobacco extract with dSPE cleanup|
|Inj. Vol.:||1.0 µL splitless (hold 1.0 min)|
|Liner:||Premium 4 mm single taper w/wool (cat.# 23303.5)|
|Inj. Temp.:||250 °C|
|Oven Temp.:||Rxi-5Sil MS: 90 °C (hold 1.0 min) to 310 °C at 5 °C/min (hold 2.0 min)|
Rtx-200: 95 °C (hold 1.0 min) to 315 °C at 5 °C/min (hold 2.0 min)
|Carrier Gas||He, corrected constant flow (2 mL/min)|
|Modulator Temp. Offset:||+20 °C|
|Second Dimension Separation Time:||3 sec|
|Hot Pulse Time:||0.9 sec|
|Cool Time between Stages:||0.6 sec|
|Transfer Line Temp.:||300 °C|
|Source Temp.:||225 °C|
|Electron Energy:||70 eV|
|Mass Defect:||-20 mu/100 u|
|Acquisition Range:||45 to 550 amu|
|Spectral Acquisition Rate:||100 spectra/sec|
|Instrument||LECO Pegasus 4D GCxGC-TOFMS|
|Sample Preparation||QuEChERS Extraction:|
A 2 g sample of tobacco was weighed into a 50 mL polypropylene centrifuge tube (cat.# 26239). After the addition of 10 mL of organic-free water to the sample, 100 µL of QuEChERS internal standard mix for GC-MS analysis (cat.# 33267) was added to each sample. Next, 10 mL of acetonitrile was added and the samples were vortexed for 30 min. Immediately after vortexing, pre-packaged QuEChERS European EN 15662 method formulation extraction salts (cat.# 26236) were added to each centrifuge tube. The tubes were immediately shaken for 1 min and then centrifuged for 5 min at 3000 g.
A 1 mL aliquot of the extract was fortified with 5 µL of an anthracene standard (cat.# 33264) and added to a dSPE tube containing 150 mg MgSO4, 25 mg PSA and 7.5 mg GCB (cat.# 26218). The tubes were gently shaken for 2 min and then centrifuged for 5 min using a Q-sep 3000 centrifuge (cat.# 26230). A 0.5 mL portion of the supernatant extract was removed and placed into an autosampler vial and 5 µL of a 5% formic acid solution in acetonitrile was added to each sample prior to analysis.
|Notes||Rtx-200 (cat.# 15124) is a 2 m column. A 1.3 m section was cut off and used as the second dimension column.|