Automated filtering scripts based on accurate mass applied to comprehensive two-dimensional gas chromatography coupled to high resolution mass spectrometry for group-type analysis of naphthenic acids

Author(s)

Sampaio, Naiara Mariana Fiori Monteiro ; Crucello, Juliana ; Medeiros Junior, Iris ; Carvalho, Rogerio Mesquita ; Hantao, Leandro Wang

• Document type: Journal article
• Source: JOURNAL OF CHROMATOGRAPHY OPEN; v. 2, p. 11-pg., 2022-11-01.

Abstract

In this work, it is reported the detailed evaluation of filtering scripts for comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry (GCxGC-HRMS). x GC-HRMS). Automated scripts were built to perform group-type analysis of naphthenic acids (NAs) in complex mixtures, like produced water (PW) samples. The logical operations were based on high-resolution mass spectral information acquired by using electron ionization (EI) and chemical ionization in the positive mode (PCI). The most common derivatization methods were carefully evaluated for group-type analysis. The performance of the scripts was evaluated using the rank metric (RM), wherein the sum-normalized absolute difference was calculated for true positives versus false positives. The best performing approach for qualitative analysis was attained by combining the derivatization with N-tert-butyldimethylsilyl- N-methyltrifluoroacetamide (MTBSTFA) with EI due to the high intensity and characteristic pseudo-molecular ions (even-electron [M-57]+ + ). The data obtained supported the development of selective scripts, exhibiting accuracy values above 98 % and 88 % for the reference and unknown PW samples, respectively. The retention pattern of GCxGC x GC was also used as a discriminant parameter for ambiguous identification, highlighting the synergy between GCxGC x GC and HRMS. The proposed scripts are an interesting alternative to profile 154 classes of MTBSTFA-derived NAs, which considerably reduced the time spent in manual data curation and annotation, while improving the reliability of the results. This is an important step to aid in the development of standard methods for the study and regulation of water-soluble compounds found in PW samples. (AU)

• FAPESP's process: 14/50867-3 - INCT 2014: National Institute of Science and Technology in Bioanalysis
• Grantee: Marco Aurelio Zezzi Arruda
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/01064-6 - Analytical developments to study real samples from oil spill in Pernambuco coast: simulations, chemical characterization and ecotoxicity bioassays
• Grantee: Leandro Wang Hantao
• Support Opportunities: Regular Research Grants