Scott spray chamber

Meltwater chemistry was analyzed to examine changes along the volcanic gradient. Analyses included in situ pH, temperature, and chemical composition of ice samples. Basic measurements of the physical and chemical parameters of meltwater were made with a temperature-calibrated pH and conductivity meter (WTW, Weilheim, Germany). Assays for NH₄⁺, NO²⁻, NO³⁻, total dissolved nitrogen (TDN), soluble reactive phosphorus (SRP) and dissolved organic carbon (DOC) from each sample were performed as described elsewhere [20 (link)] by ion chromatography in an 861 Advance Compact IC system (Metrohm AG, Herisau, Switzerland). The measurements of major, minor, and trace elements (Ag, Al, As, B, Ba, Be, Bi, Br, C, Ca, Cd, Cl, Co, Cr, Cu, Fe, Ga, Ge, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sc, Se, Sr, Ti, V, Y, Zn, and Zr) (Table S1) were performed by inductively coupled plasma-mass spectrometry (ICP-MS) on a PerkinElmer ELAN9000 ICP-MS quadrupole spectrometer as in [14 (link)]. The samples were introduced into the ICP-MS via a RytonTM cross-flow nebulizer (PerkinElmer, Waltham, MA, USA), Scott spray chamber (PerkinElmer), and Cetac ASX-510 autosampler (Omaha, NE, USA).

The geochemistry of every ice core sample was characterized using several complementary techniques.
Assays for NH₄⁺, NO₂⁻, NO₃⁻, SO₄²⁻, soluble reactive phosphorus (SRP), and dissolved organic carbon (DOC; Table 2) were carried out by ion chromatography in an 861 Advance Compact IC system (Metrohm AG, Herisau, Switzerland). Chromatograms were registered with the Metrohm IC Net 2.3 SR6 software. Ions were quantified with internal and external standards prepared from Certified Standard Solutions (TraceCERT®; Merck, Darmstadt, Germany; Garcia-Descalzo et al., 2013 (link)).
The concentration of major (Cl, S, C, K, Na, P, Xe, Mg, Ca, Fe, Co, Mn, Ti, Cr, and Ni), minor, and trace elements (Supplementary Table S1) was quantified by inductively coupled plasma-mass spectrometry (ICP-MS) on a PerkinElmer ELAN9000 ICP-MS quadrupole spectrometer. The samples were introduced into the ICP-MS via a RytonTM cross-flow nebulizer (PerkinElmer, Waltham, MA, United States), Scott spray chamber (PerkinElmer), and Cetac ASX-510 autosampler (Omaha, Nebraska, United States; García-Lopez et al., 2021a (link)).