‰ for KNO3 and 1.2 ‰ for NaNO3) compared to normal standard solutions (0.2 ‰ for both KNO3 and NaNO3). Injecting raw river water from an isotopic enrichment experiment with NH4Cl, which was not evaporated to pre-concentrate nitrate, also showed an injection peak after 265 s and no measurable nitrate peak (Figure