APGC is a soft ionization technique which produces lower levels of fragmentation compared to traditional EI. Working in dry conditions, APGC typically produces spectra with strong radical cation molecular ions that facilitates the direct comparison of historic, archival EI data from many different sources. The abundant nature of these ions makes it possible to generate specific and sensitive MRM transitions for petroleum biomarkers which provide information on the biological source of the oil, the environment in which the parent organic matter was deposited, and the thermal history of the buried organic matter. Knowledge of these properties is especially useful in upstream applications and is ultimately linked to the economic productivity from a particular geological location.

The universal ionization source offered on all Waters instrumentation facilitates the quick and simple coupling of APGC, UPLC or UPC2 on a single MS platform. Coupled with Xevo TQ-S, APGC enables low-level quantification of petroleum biomarkers that have proved challenging to analyze using GC-MS systems, allowing unambiguous confirmation of the deposition environment from which the oil originates.