News from LabRulezGCMS Library - Week 30, 2026

This presentation investigates how the characteristic odor of a human body changes during the transition from life (ante-mortem) to decomposition (post-mortem). The researchers focused on identifying volatile organic compounds (VOCs) released during the early post-mortem period and determining when the scent profile changes from that of a living person to that associated with human remains. Understanding this transition is particularly important for improving search and rescue operations, where distinguishing between living victims and deceased individuals is essential for deploying search-and-rescue dogs and human remains detection dogs effectively.

To study this process, VOC samples were collected from body donors at both a morgue and an outdoor decomposition research facility (REST). Air samples were collected using sorbent tubes and ACTI-VOC pumps after controlled VOC accumulation and sampling periods. Chemical analysis was performed using thermal desorption comprehensive two-dimensional gas chromatography coupled with mass spectrometry (TD-GC×GC-MS). The analytical system employed a Restek Rxi®-624Sil MS first-dimension column and a Stabilwax® second-dimension column, with electron ionization (70 eV) mass spectrometry covering a mass range of 29–300 amu at an acquisition rate of 250 spectra/s. Data processing combined ChromaTOF software with RStudio for feature alignment, normalization, filtering, and manual verification of VOC profiles.

The study identified 827 volatile organic compounds, representing a wide range of chemical classes including nitrogen-containing compounds, esters, halogenated compounds, aromatics, alcohols, ketones, aldehydes, sulfur-containing compounds, ethers, and acids. By comparing experimentally detected VOCs with compounds previously reported in the literature for both living humans and decomposing remains, the researchers identified 33 trans-mortem VOCs that characterize the transition between ante-mortem and post-mortem odor. VOC profiles were then monitored throughout decomposition for individual donors, allowing the team to visualize how the relative contributions of ante-mortem, trans-mortem, and post-mortem compounds evolved over time.

The results showed that ante-mortem and trans-mortem VOCs remained detectable during the earliest stages after death, while post-mortem odor compounds became increasingly dominant after approximately Accumulated Degree Days (ADD) 73.4, corresponding to Experimental Day 3. The authors conclude that although these findings improve our understanding of early decomposition odor chemistry, additional studies across different environments and seasonal conditions are needed to standardize VOC-based approaches and further support forensic investigations and search-and-rescue applications.

4. Shimadzu: Gas Analysis for CO2 Conversion Using a GI-30 Auto Gas Injector

• Application note
• Full PDF for download

The catalytic conversion of carbon dioxide (CO2) to methanol (MeOH) and to hydrocarbons has garnered significant attention as a strategy to realize a sustainable chemical industry. Analytical targets in CO2 conversion studies typically include carbon monoxide (CO), hydrocarbons, alcohols, and other reaction products. Selection of appropriate column and detector combinations must therefore be guided by the nature and concentrations of target analytes.

In this application news, we demonstrate simultaneous analysis on two parallel columns by using INJ2-way branch unit to permit detection of CO and hydrocarbons together with alcohols such as MeOH. We also present a simplified measurement approach employing a single-column configuration equipped with a thermal conductivity detector(TCD).

System Configuration and Analysis Conditions

Two reaction schemes using CO2 as feedstock were envisaged: (1) MeOH synthesis and (2) conversion to hydrocarbons. The instrumentation comprised the Auto Gas Injector GI-30 and the SPI inlet, which minimizes air ingress and sample adsorption (Fig. 1). 

For the MeOH synthesis application, a Jetanizer -FID—which permits detection of CO and CO2 that are not observable by a conventional FID—was employed. A MICROPACKED-ST packed column provides separation of CO from O2 (ambient contamination); however, higher-boiling hydrocarbons and alcohols such as MeOH are not eluted from this column. To achieve comprehensive analysis, the injector was splitted and an SH-Q-BOND capillary column was used to resolve hydrocarbons and MeOH concurrently. The injection-port splitting is implemented using dedicated hardware (Application News No. 01-00661-EN). 

For the conversion to hydrocarbons scenario, when analytes are permanent gases and C3-or-smaller hydrocarbons, quantitative analysis can be performed with a single MICROPACKED-ST column coupled to a TCD. The TCD responds to differences in thermal conductivity between carrier and analyte gases; measuring low–thermal-conductivity species such as hydrocarbons requires a carrier gas with high thermal conductivity (helium or hydrogen) (Table 1). The Brevis GC-2050 TCD uses a single filament design, resulting in rapid baseline stabilization (~10 minutes), which is advantageous for routine operation.

Conclusion

Using INJ2-way branch unit enables simultaneous analyses using distinct column-detector combinations within a single chromatographic cycle, permitting comprehensive quantification of reaction products from CO2 conversion— ranging from CO and hydrocarbons to alcohols such as MeOH. For analyses restricted to hydrocarbons up to C3, a streamlined single-column TCD configuration provides sufficient separation and sensitivity. It should be noted that MeOH and hydrocarbons of carbon number ≥ C4 may adsorb or be retained on the MICROPACKED-ST column; periodic column conditioning is therefore recommended.