HaloSeeker 1.0, a user-friendly software to highlight halogenated chemicals in non-targeted high resolution mass spectrometry datasets.

In the present work, we address the issue of non-targeted screening of organohalogenated chemicals in complex matrices. A global strategy aiming to seek halogenated signatures in full scan high resolution mass spectrometry (HRMS) fingerprints was developed. The resulting all-in-one user-friendly application, HaloSeeker 1.0, was developed to promote the accessibility of associated in-house bioinformatics tools to a large audience. The ergonomic web user interface avoids any interactions with the coding component while allowing interactions with the data, including peak detection (features), deconvolution and comprehensive accompanying manual review for chemical formula assignment. HaloSeeker 1.0 was successfully applied to a marine sediment HRMS dataset acquired on a LC-HESI(-)-Orbitrap instrument (R=140,000@200). Among the 4532 detected features, 827 were paired and filtered in 165 polyhalogenated clusters. HaloSeeker was also compared to three similar tools and showed the best performances. HaloSeeker ability to filter and investigate halogenated signals was demonstrated and illustrated by a potential homologue series with C12 Hx Bry Clz O2 as a putative general formula.