Simultaneous determination of seven perfluoroalkyl carboxylic acids in water samples by 2,3,4,5,6-pentafluorobenzyl bromide derivatization and gas chromatography-mass spectrometry

Magnetic fluorinated mesoporous metal-organic frameworks for rapid derivatization-assisted GC-MS analysis of perfluoroalkyl carboxylic acids in harsh water environment

A novel magnetic mesoporous fluorinated metal-organic framework material (Fe3O4@MIP-206-F) has been synthesized specifically for application as an adsorbent for perfluoroalkyl carboxylic acids (PFCAs) extraction by magnetic solid-phase extraction (MSPE). The carefully designed Fe3O4@MIP-206-F material features an appropriate porosity, open metal sites of Zr, and functional groups (fluorine and amino) conducive to the adsorption process. The distinctive architecture of the material endows it with exceptional extraction capabilities for PFCAs. Adsorption mechanisms encompass acid-base interactions, hydrophobic interactions, F-F interactions, electrostatic interactions, and size complementarity. Optimization of key parameters has significantly improved the extraction efficiency of MSPE. When coupled with gas chromatography-mass spectrometry (GC-MS), MSPE offers rapid and highly sensitive analysis of PFCAs. The method demonstrates wide linear range (0.050-50 ng mL-1), low detection limits (0.0010-0.0019 ng mL-1), good recoveries (86.7 % to 111 %), and exceptional intra- and inter-day precision. This approach accurately quantifies PFCAs in lake water and groundwater samples, enabling precise assessment of environmental contamination levels and supporting targeted remediation efforts.

Fabrication of molecularly imprinted carbon nanotubes integrating ionic liquids for efficient detection of perfluoroalkyl carboxylic acid in environmental water

It is extremely significant while challenging to accurately detect low-levels of perfluoroalkyl carboxylic acid compounds (PFCAs) in environmental water. Herein, adopting perfluorotetradecanoic acid as the dummy template, selective molecularly imprinted composites (CNTs@ILs@MIPs) grafted carbon nanotubes integrating hydrophilic ionic liquids were successfully prepared via surface imprinting and dummy-template imprinting techniques. The obtained CNTs@ILs@MIPs were applied as selective extraction adsorbent for specifically extract PFCAs in environmental water coupled with gas chromatography-mass spectrometry quantification. Detailed studies were conducted on the main preparation parameters and extraction conditions. The CNTs@ILs@MIPs displayed excellent adsorptivity, and the established method exhibited low LODs (0.60-1.64 ng L-1), wide linearity with R2 above 0.9994, and satisfactory adsorption recoveries (80.5-112.5%) for seven PFCAs. This proposed method provides a new applicable approach for the detection of targeted pollutants in environmental water by utilizing the high affinity and recognition ability of molecularly imprinted carbon nanotube functional materials modified with ionic liquids.

An overview on human exposure, toxicity, solid-phase microextraction and adsorptive removal of perfluoroalkyl carboxylic acids (PFCAs) from water matrices

Perfluoroalkyl carboxylic acids (PFCAs) are sub-class of perfluoroalkyl substances commonly detected in water matrices. They are persistent in the environment, hence highly toxic to living organisms. Their occurrence at trace amount, complex nature and prone to matrix interference make their extraction and detection a challenge. This study consolidates current advancements in solid-phase extraction (SPE) techniques for the trace-level analysis of PFCAs from water matrices. The advantages of the methods in terms of ease of applications, low-cost, robustness, low solvents consumption, high pre-concentration factors, better extraction efficiency, good selectivity and recovery of the analytes have been emphasized. The article also demonstrated effectiveness of some porous materials for the adsorptive removal of the PFCAs from the water matrices. Mechanisms of the SPE/adsorption techniques have been discussed. The success and limitations of the processes have been elucidated.

A Rapid Derivatization for Quantitation of Perfluorinated Carboxylic Acids from Aqueous Matrices by Gas Chromatography-Mass Spectrometry

Ultrashort-chain perfluorinated carboxylic acids (PFCAs) are receiving more attention due to their ever-increasing presence in the environment. Methods have been established for the analysis of short- and long-chain PFCAs, while robust quantitation of ultrashort-chain species is scarce. Here, we develop a novel derivatization method using diphenyl diazomethane for quantitation of C2-C14 PFCAs in aqueous matrices. The method is highlighted by rapid completion of derivatization (<1 min) and retention and separation of ultrashort-chain (C2/C3) PFCA derivatives using H₂ carrier gas (R > 1.5). A weak anion exchange solid-phase extraction procedure for analyte recovery from representative aqueous samples was developed and validated by spike and recovery from ultrapure water, synthetic ocean water, and simulated denuder extracts used for collecting gaseous PFCAs. Recoveries for PFCAs ranged from 83 to 130% for the majority of analytes and matrices. The instrument detection limits (IDLs) range from 8 to 220 fg per injection, and method detection limits (MDLs) range from 0.06 to 14.6 pg/mL for 500 mL aqueous samples, which are within an order of magnitude to conventional LC-MS/MS methods. The method was applied to the analysis of real samples of tap water, rainwater, ocean water, and annular denuder extracts. The overall method provides a cost-effective alternative to conventional LC-MS/MS methods, overcoming the typical GC-MS drawbacks of high detection limits and long sample preparation times while being able to simultaneously analyze the complete spectrum of environmentally relevant PFCAs.