GC-IMS dataset of pooled human urine for chromatographic alignment studies

This dataset contains gas chromatography–ion mobility spectrometry (GC-IMS) measurements acquired from pooled human urine samples. The data were generated to support methodological research on chromatographic alignment and signal processing approaches applied to GC-IMS data.

Urine samples were collected from eleven healthy volunteers (five female and six male). First-morning fasting urine was obtained and pooled under controlled conditions. The pooled sample was aliquoted into multiple vials and stored frozen until analysis. Prior to measurement, each vial was prepared with sodium chloride to enhance volatilization, an internal standard solution (2-decanone), and hydrochloric acid. The prepared samples were then analysed using headspace GC-IMS. The study protocol was approved by the Ethics Committee of Hospital de Reus (study approval no. 074/2018).

Measurements were performed using a FlavourSpec® GC-IMS instrument equipped with a non-polar capillary GC column (FS-SE-54-CB). Ionization was achieved using a tritium β-radiation source and ion mobility separation was carried out in a drift tube operated under a constant electric field. Headspace sampling was conducted with an automated PAL-xt autosampler after thermal incubation of the sealed vials. Nitrogen was used both as carrier and drift gas. Volatile compounds were separated chromatographically before entering the ionization region and subsequently resolved in the ion mobility drift tube according to their mobility.

Each measurement produced a two-dimensional signal matrix in which the axes correspond to gas-chromatographic retention time and ion mobility drift time, respectively. Signal intensity values represent the recorded ion current detected by a Faraday plate. Spectra were acquired in positive ion mode with temporal averaging of scans during acquisition. A blank measurement was performed after each sample to minimise carry-over and confirm recovery of the reactant ion peak.

Each dataset entry corresponds to a full GC-IMS measurement lasting approximately 32 minutes. The resulting matrices contain roughly 22 million intensity values per measurement. Although the full retention-time range is preserved in the original files provided in this repository, subsequent data processing and analysis focus on the chromatographic region up to approximately 23 minutes of retention time. This truncation of the retention-time axis is applied during data processing using the GCIMS software package.

In addition to the raw measurement files, the repository also includes a CSV file containing the inverse reactant ion peak (RIP) chromatograms extracted from the GC-IMS data within the retention-time range of approximately 0–23 minutes. These processed signals may facilitate rapid testing and benchmarking of chromatographic alignment algorithms without requiring full reconstruction of the two-dimensional data matrices.

These data can be used for the development and evaluation of algorithms for chromatographic alignment, preprocessing, peak detection, chemometric analysis, and other computational approaches relevant to GC-IMS data processing.

The dataset is associated with a research study focused on chromatographic alignment methodologies. Additional information about file organisation, variable definitions, and preprocessing steps is provided in the accompanying documentation included in the repository.