Abstract
RATIONALE: An “Open Access”-like mass spectrometric platform to fully utilize the simplicity of the manual open port
sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure
ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and
relatively low-cost mass spectrometry system introduced here fills this void.
METHODS: Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data
files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendorprovided
software libraries. Sample classification based on spectral comparison utilized the spectral contrast angle
method.
RESULTS: Using the developed software platform near real-time sample classification is exemplified using a series of
commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative
ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan
positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle
statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation.
CONCLUSIONS: This work illustrates that an open port sampling interface/mass spectrometer combination, with
appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis
system suitable for the non-expert user and near real-time sample classification via database matching. Published in
2016. This article is a U.S. Government work and is in the public domain in the USA.
