Overcoming challenges in the analysis of the ubiquitous emerging contaminant trifluoroacetic acid employing trap column liquid chromatography tandem mass spectrometry

Ramadan Sayed; Ahmed A Omran; Rabie S Farag; Hend A Mahmoud; Mostafa Soliman

doi:10.1016/j.jhazmat.2025.137976

Overcoming challenges in the analysis of the ubiquitous emerging contaminant trifluoroacetic acid employing trap column liquid chromatography tandem mass spectrometry

J Hazard Mater. 2025 Jul 5:491:137976. doi: 10.1016/j.jhazmat.2025.137976. Epub 2025 Mar 19.

Authors

Ramadan Sayed¹, Ahmed A Omran², Rabie S Farag², Hend A Mahmoud³, Mostafa Soliman⁴

Affiliations

¹ Department of Chemistry, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt; Agricultural Research Center, Central Laboratory of Residue Analysis of Pesticides and Heavy Metals in Foods (QCAP Egypt), 7-Nadi Elsaid St, Dokki, Giza, Egypt. Electronic address: ramadan.sayed@qcap-egypt.com.
² Department of Chemistry, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.
³ Agricultural Research Center, Central Laboratory of Residue Analysis of Pesticides and Heavy Metals in Foods (QCAP Egypt), 7-Nadi Elsaid St, Dokki, Giza, Egypt.
⁴ Agricultural Research Center, Central Laboratory of Residue Analysis of Pesticides and Heavy Metals in Foods (QCAP Egypt), 7-Nadi Elsaid St, Dokki, Giza, Egypt. Electronic address: mostafa.soliman@qcap-egypt.com.

PMID: 40120281
DOI: 10.1016/j.jhazmat.2025.137976

Abstract

Trifluoroacetic acid (TFA) is a ubiquitous ultra-short chain emerging contaminant and a widely observant pollutant in the environment. Its analytical determination usually encounters two main challenges, difficulties of chromatographic separation on reversed-phase C18 columns and the false positive results in blank samples due to TFA ubiquitous nature. This study presents the successful separation of TFA on Poroshell 120 EC-C18, 3.0 × 50 mm, 2.7 μm column, enabling the determination of TFA along with other long-chain contaminants. The application of trap column technique resulted in delaying the elution of TFA contamination arising from mobile phase later than the retention time of the target analyte. For direct samples injection, acetonitrile and methanol (MeOH) with acid and alkali modifications were evaluated as dilution solvents. 6 mL of 0.1 % NH4-modified MeOH and 4 mL of water sample provided the optimum TFA peak shape. The method was successfully validated and satisfied the requirements of SANTE/11312/2021 (V2) guidelines. The evaluated criteria were specificity and selectivity, trueness, precision, calibration linearity, limit of quantification (LOQ), and matrix effect. The validated method was applied to monitor the concentration levels of TFA in 30 real samples. The detected concentrations were <LOQ of the method in all the positively tested samples.

Keywords: Analytical method validation; Emerging contaminants; LC-MS/MS; Trap column technique; Trifluoroacetic acid; Ultra-short chain pollutants; Water.