Methane concentration
Sulfate concentration
Sulfide concentration
Stable isotopes: ¹²C/¹³C analysis of CH₄ and CO₂
Total Organic Carbon / Nitrogen (TOC / TN)
DIC, Dissolved Inorganic Carbon
Volatile fatty acids (VFA) and sulfate in porewater samples
Pyrite, iron sulfide, elemental sulfur
Reactive iron
²¹⁰Pb, ¹³⁷Cs

Methane concentration

Take a sediment sample of exactly 3 ml with a 5 ml (or 3 ml) syringe with the luer tip removed.

Transfer the sample to a 20 ml serum vial containing 6 ml NaOH (2.5 %) or 6 ml milli-Q H2O 1). Close the vial immediately with a rubber stopper and an aluminum crimp seal.

The gas peaks are integrated by an integrator (Hewlett Packard 3395). Methane elutes at 0.65 min.

The concentration is calculated from the integrated area (A) of the methane peak by comparison with a standard curve (based on 100 ppmV and 1000 ppmV methane standards) and corrected for background.

Calculation of the CH₄ concentration expressed as amount per volume sediment:






¹⁾ Effects of sample treatment with H₂O instead of NaOH on the measured CH₄ concentration were investigated in various test series applying sample storage times of a few hours up to 0.5 y. Differences of measured CH₄ concentrations between H₂O treatments and NaOH controls were never observed.

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