Exhaled breath condensate (EBC) is a promising, non-invasive, diagnostic sample obtained by condensation of exhaled breath. In contrast to nasal or throat swabs, bronchoalveolar lavage, sputum or saliva, EBC is easily accessible in large quantities. Hence, it can be applied to target the protein and (bio-)nanoparticle content released from the respiratory tract of an individual. Gas-phase electrophoresis on a nano Electrospray Gas-phase Electrophoretic Mobility Molecular Analyzer (nES GEMMA) also known as nES Differential Mobility Analyzer (nES DMA) separates single-charged, aerosolized, surface-dry analytes in the gas-phase at ambient pressure according to the particle size (Kaufman et al, 1996). Prior separation, analytes are electrosprayed from a volatile electrolyte solution followed by charge equilibration in a bipolar atmosphere induced by e.g. 210Po, a soft X-Ray charger or a bipolar corona discharge process (e.g. Weiss et al, 2020). Previous experiments have demonstrated the applicability of such a setup for the characterization of proteins and protein aggregates, viruses, virus-like particles, liposomes, extracellular vesicles and similar (bio-)nanoparticles. Besides information on surface-dry particle size (EM diameter), analyte and sample heterogeneity and number-based particle concentrations, information on particles’ molecular weight values can be gathered by application of a respective correlation (e.g. Bacher et al, 2001). It was therefore the aim of our research to characterize EBC by application of a nES GEMMA setup. EBC was collected via a prototype instrument delivering cooling temperatures down to -20°C via a Peltier element from a voluntary male donor at several time points resulting in nES GEMMA spectra as exemplified in Figure 1. Fitting of Gaussian peaks to resulting spectra enabled us to identify more than 30 compounds contributing to signals recorded upon gas-phase electrophoresis between 3 and 18 nm surface-dry particle diameter. Application of an EM diameter / molecular weight correlation subsequently yielded molecular weight of these compounds in the range of approx. 8 - 850 kDa. Hence, results in good approximation with data reported by Lacombe et al were obtained (Lacombe et al, 2018). In this context, it is of note that for Ovalbumin a limit of detection value (LOD) of 9 nM was determined for applied nES GEMMA settings and that EBC was pre-concentrated twentyfold prior gas-phase electrophoresis via spin filtration and mixing with ammonium acetate (10 kDa molecular weight cutoff filters, final ammonium acetate concentration for gas-phase electrophoresis at 40 mM, pH 8.4). We believe that the combination of EBC collection and gas-phase electrophoresis will offer an attractive sampling, measurement and diagnostic tool in the near future.