Fig. 4From: Validation of passive samplers for monitoring of acetic and formic acid in museum environmentsA sample ion chromatogram (SE) obtained after sampling the indoor air at the National Museum of Slovenia. The \(\hbox {SO}_4^{2-}\) signal, observable in this chromatogram, was quantified using a different chromatographic method, as it was not separated from the \(\hbox {CO}_3^{2-}\) signal in this caseBack to article page