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doi:10.2204/iodp.proc.329.204.2017

Appendix A

Preparation of standards for gas chromatograph calibration

1. PFT dilution series in methanol (MEOH):
• 10^–2 = 9.9 mL MEOH + 0.1 mL PFT
• 10^–4 = 9.9 mL MEOH + 0.1 mL 10^–2 PFT
• 10^–6 = 9.9 mL MEOH + 0.1 mL 10^–4 PFT
• 10^–8 = 9.9 mL MEOH + 0.1 mL 10^–6 PFT
2. Transfer 10 µL aliquots of each dilution into duplicate 20 mL capacity headspace vials, seal each with a polytetrafluoroethylene (PTFE)/silica septum, and label appropriately.
3. Heat the vials at 70°C for 30 min along with the 3 m gas-tight plastic syringes and needles that will be used for analysis. A rotation of 4 needles may be used, provided that each is allocated a 30 min heating period between sequential usages.
4. Inject either 0.5, 1.0, or 2.0 mL of each standard’s headspace gas into the gas chromatograph on separate runs using the 3 mL plastic syringe affixed with a luer fitting for stainless steel needles.
5. Integrate the peak area for each injection. Convert the PFT:MEOH dilution to PFT(g) using the following formula:

PFT(g) = Vinjected × Cstd,

where

• V_injected = standard volume injected,
• C_std = ρ_PFT × df × V_{STD_solution}/V_headspace in grams PFT/volume headspace,
• ρ_PFT = density of PFT (i.e., 1.78 g/L),
• df = dilution factor, ratio (vol:vol) of pure PFT:total solution,
• V_{STD_solution} = volume of diluted standard solution in vial, and
• V_headspace = volume of headspace.
6. Plot log[PFT(g)] against log[peak area] and perform regression analysis to determine the calibration sensitivity. See Appendix B.

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