Agilent 8 900 triple quadrupole

The filtered porewater was aliquoted in the glovebox and conditioned for subsequent chemical analysis of sulfide, ferrous iron, major cations and anions, and trace elements. Sulfide was analyzed using the Cline method (Cline, 1969 (link)) and ferrous iron using the ferrozine assay (Stookey, 1970 (link)) both with a UV-2501PC spectrometer (Shimadzu, Kyoto, Japan). Major anions and cations were detected and quantified by Ion Chromatography. An IonPac^®CS13A-5 μm cation-exchange column (Thermo Fisher Scientific Inc., Waltham, Massachusetts, United States), with as gradient eluent 20 mM methane sulfonic acid, was used for major cations, whereas an IonPac^® AS18-4 μm anion-exchange column (Thermo Fisher Scientific Inc., Waltham, Massachusetts, United States), with as gradient eluent KOH (from 0.0 to 30 mM), was used for major anions. Trace metals Al, Co, Cr, Cu, Fe, Mn, Mo, Ni, Si, Sr, Zn, were measured using inductively coupled plasma mass spectrometry (ICP-MS) on an Agilent 8,900 Triple Quadrupole (Agilent Technologies Inc., Santa Clara, United States), with all samples prepared in dilutions with 0.1 M HNO₃ (final concentration, ultra-pure grade, MilliporeSigma, Merck KGaA, Darmstadt, Germany).