During the continuous flow analysis (CFA) campaigns of the EGRIP ice core at the University of Bern, Switzerland in 2018, 2019 and 2020, subsamples for the analysis of ion concentrations were collected in a 2 – 5 cm resolution from the meltwater. The subsamples were collected into pre-cleaned 10 ml vials and were kept frozen during storage and transportation to the Alfred-Wegener-Institut in Bremerhaven, Germany. Prior to the analysis, the vials containing the discrete decontaminated aliquots of the ice core were melted at room temperature. The vials were then placed into an autosampler for the measurements. Simultaneous analysis of anions and cations was performed using a two-channel Dionex ICS 5000+ reagent-free HPIC system (Thermo Fisher). For the anion (cation) determination an AERS 500 2mm suppressor and ADRS 600 2mm suppressor (CERS 500 2mm and CDRS 600 2mm) together with the Dionex IonPac AG18-Fast-4µm guard column and the AS18 fast-4µm column (IonPac CG12A-5µm guard column and the CS12A-5µm column ) and the Dionex IonPac AS18-Fast-4µm analytical column (IonPac CS12A-5µm column) were used. For the anions an isocratic mode was used. For the cations the mode was changed from isocratic to gradient. Also, the eluent concentration was modified in-between measurements in order to improve the quality of the data. The measurements were calibrated with seven internal standards, prepared from available anion and cation standards. Premixed external standards were used for quality control. In this study, the IC provided a quantitative analysis of the concentration of Na+, NH4+, K+, NO3-, , F−, MSA−, C1−, Br−, and SO42− with an accuracy of 10 %. The accuracy for of Ca2+ and Mg2+ measurements is much lower. We recommend not to use these values. The concentrations of bromide and fluoride are close to the detection limit and are suggest to consider with great care. For details on the sampling protocol or potential contamination during the CFA campaign we ask the users to get in touch with the authors.

The depth information of samples was not available at the time of submission and will be added in due course.