A method (RT_A) for synchronizing data for a plurality of gas samples, e.g. breath samples, with volatile organic compounds. The data comprises chromatographic data indicative of molecule elution times, and preferably also mass spectrography data. The method comprises identifying or selecting (I_MM) marker molecules, e.g. 5-20 molecules, preferably easily identifiable molecues for each of the plurality of gas samples, and clustering (CL) the plurality of gas samples into a plurality of clusters according to a clustering criterion, e.g. including additional information such as time of obtaining the data and/or analzing equipment used. Next, a first correction of retention time deviations (P_C1) is performed on the data for the gas samples between clusters by using the marker molecules as anchor points, so as to provide a coarse reduction of retention time deviations (d) between the data for the gas samples. Finally, a second correction of retention time deviations (P_C2) on the data for the gas samples, so as to further reduce retention time deviations (d) between the data for the gas samples, e.g. by using standard software packages. The method can reduce significant retention time deviations so as to allow e.g. breath sample fingerprints obtained by different equipment at different periods of time to be compared in one database for use on a digital platform (DP) such as the HSDP.La présente invention concerne un procédé (RT_A) permettant de synchroniser des données pour une pluralité d'échantillons de gaz, par exemple des échantillons d'haleine, comprenant des composés organiques volatils. Les données comprennent des données chromatographiques indiquant les temps d'élution des molécules, et de préférence également des données de spectrographie de masse. Le procédé consiste à identifier ou à sélectionner (I_MM) des marqueurs moléculaires, par exemple de 5 à 20 molécules, de préférence des molécules facilement identifiables pour chacun de la pluralité d'échantillons
