Methods and materials
Instrumentation and sample materials. A gas chromatograph (Agilent 6890, Santa Clara, CA) with a G1888 (Agilent) headspace autosampler and 20-mL sample vials were
used for the experiments. The column used for these amine analyses was a Restek RTX-5 AMINE (Bellefonte, PA), 30 m x 530 µm
x 5 µm film thickness. Triethylamine (TEA) was purchased from FisherScientific (Division of Thermo Fisher Scientific, Waltham,
MA); DMSO, n-butylamine, and allylamine were purchased from Sigma-Aldrich (St. Louis, MO); Water (high-performance liquid chromatography
grade) was purchased from J.T. Baker (Phillipsburg, NJ); and dimethylformamide (DMF) was purchased from EMD Science (Darmstadt,
Germany).
Table I: Headspace parameters
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Stock TEA samples were prepared by diluting 138 µL into 100 mL of diluent, where the diluent was different ratios of either
DMSO:water or DMSO:0.01M sodium hydroxide (NaOH). Analysis samples were further diluted 1 mL into 100 mL with the appropriate
diluent for the experiment. This dilution resulted in a final TEA concentration of 0.0100 mg/mL. Stock n-butylamine samples were prepared by diluting 213 µL into 250 mL of diluent, where the diluent was either water, 0.1M NaOH,
or DMSO. Analysis samples were further diluted 1 mL into 25 mL with the appropriate diluent for the experiment (different
ratios of DMSO:0.1M NaOH or water). This dilution resulted in a final n-butylamine concentration of 0.0252 mg/mL. Stock allylamine samples were prepared by diluting 300 µL into 100 mL of diluent,
where the diluent was either 0.001M NaOH, 0.01M NaOH, DMF (or DMSO), or ratios of DMF (or DMSO):base. Analysis samples were
further diluted 1 mL into 100 mL with the appropriate diluent for the experiment. This dilution resulted in a final allylamine
concentration of 0.0228 mg/mL.
Figure 2
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GC method for TEA and n-butylamine: Three minutes isothermal at 50 °C, followed by a programmed temperature ramp at 20 °C/min to 130 °C, a hold period for 2
min, followed by a programmed ramp at 20 °C/m into 170 °C, a hold period for 3 min, followed by a ramp at 30 °C/min to 240
°C, with a four-minute hold period at the end of the temperature ramp. The injector temperature was 200 °C, and the detector
(i.e., FID) temperature was 300 °C with a constant column flow of 3.8 mL/min of helium.
Figure 3
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GC method for allylamine: Eight minutes isothermal at 45°C, followed by a programmed temperature ramp at 40 °C/min to 240 °C, with a four-minute hold
period at the end of the temperature ramp. The injector temperature was 180 °C, and the detector (i.e., FID) temperature was
300 °C with a constant column flow of 3.8 mL/min of helium. Headspace parameters are shown in Table I.
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