Measure chain for exhaled breath collection and analysis: A novel approach suitable for frail respiratory patients

Exhaled breath analysis, a non-invasive diagnostic procedure, is based upon a sampling device for breath collection, an apparatus for the sample delivery into the measure chamber and a gas sensor array. Here a novel approach for the design and realization of these three components is presented. The volatile mixture composing the exhaled breath is entrapped onto an adsorbing cartridge via an innovative device able to collect exhaled breath from an individual normally breathing into a mouthpiece for three minutes. This procedure is very simple and cartridges outperform sampling bags in terms of preservation and transportability. Moreover, a thermal desorption process of the volatiles adsorbed on the cartridge can partially separate them by a given temperature profile. This separation, performed by the desorbing apparatus, improves sensor resolution via a preconcentration strategy. This method improves sensor resolution. The gas sensor array employed in this work is composed by a set of eight Quartz Micro Balances (QMB) coated by eight different anthocyanins. The Pneumopipe, the innovative breath collecting device, is described and tested in a proof of concept study involving all the measure chain: two small groups of Chronic Obstructive Pulmonary Disease (COPD) patients and control individuals have been perfectly discriminated and repeated measures on the same individuals showed an optimal reproducibility as verified by calculation of the relative standard deviation.