An On-Line Solid Phase Extraction-Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of Perfluoroalkyl Acids in Drinking and Surface Waters

Abstract

An UHPLC-MS/MS multiresidue method based on an on-line solid phase extraction (SPE) procedure was developed for the simultaneous determination of 9 perfluorinated carboxylates (from 4 to 12 carbon atoms) and 3 perfluorinated sulphonates (from 4 to 8 carbon atoms). This work proposes using an on-line solid phase extraction before chromatographic separation and analysis to replace traditional methods of off-line SPE before direct injection to LC-MS/MS. Manual sample preparation was reduced to sample centrifugation and acidification, thus eliminating several procedural errors and significantly reducing time-consuming and costs. Ionization suppression between target perfluorinated analytes and their coeluting SIL-IS were detected for homologues with a number of carbon atoms less than 9, but the quantitation was not affected. Total matrix effect corrected by SIL-IS, inclusive of extraction efficacy, and of ionization efficiency, ranged between −34 and +39%. The percentage of recoveries, between 76 and 134%, calculated in different matrices (tap water and rivers impacted by different pollutions) was generally satisfactory. LODs and LOQs of this on-line SPE method, which also incorporate recovery losses, ranged from 0.2 to 5.0 ng/L and from 1 to 20 ng/L, respectively. Validated on-line SPE-LC/MS/MS method has been applied in a wide survey for the determination of perfluoroalkyl acids in Italian surface and ground waters.

Current Trends in Fully Automated On-Line Analytical Techniques for Beverage Analysis

“…In the first mode, the analytes are eluted in the same direction in which they were loaded, and in the second mode, the analytes are eluted in the opposite direction to avoid band-broadening [33]. Therefore, on-line SPE when compared to off-line SPE offers a number of advantages such as: (1) Reducing sample preparation time as conditioning, washing and elution processes are automatically performed; (2) reduces the risk of sample contamination and analyte degradation; (3) reduces analyte loss by evaporation; (4) cartridges can generally be reusable; (5) improves the accuracy, increases the detector sensitivity and makes it possible to work with much less than 1 mL of sample; (6) decrease solvent consumption and waste disposal costs, reducing operator risk of exposure to infectious or toxic solvents [34][35][36][37].…”

“…However, on-line SPE methods still present some challenges such as optimizing the pre-concentration and elution procedures to achieve satisfactory precision in a single step for different classes of compounds. Additionally, SPE on-line coupled with ultra-performance liquid chromatography (UPLC) presents disadvantages because of the elevated back pressure generated by the high flow rates used in small particle size columns (<2 µm) [34]. On-line SPE has other drawbacks including a demand for expensive equipment; exhibits low portability; coeluting of matrix interferences; absence of extracts to repeat the analysis; sorbents contamination; among others [35].…”

Evaluating the impact of a fluoropolymer plant on a river macrobenthic community by a combined chemical, ecological and genetic approach

“…For the analysis of PFAA, water samples were centrifuged and analyzed by on-line-SPE-UHPLC-MS/MS according to the method reported in Mazzoni et al (2015a). A Thermo EQuan system with a polar endcapped C18 pre-concentration column (Thermo Hypersil Gold aQ 12 μm, 20 × 2.1 mm), and a Thermo Hypersil Gold PFP analytical column (1.9 μm, 50 × 2.1 mm) were used for on-line extraction.…”

“…Quantification was performed by the isotopic dilution method using calibration curves acquired before each analytical run. Complete validation data are reported in Mazzoni et al (2015a). Briefly, the on-line SPE-UHPLC-MS/MS method gave recoveries between 87 and 134% with limits of detection (LODs) ranging from 0.2 to 5.0 ng L −1 and LOQs from 1 to 20 ng L −1 .…”

Identifying Per- and Polyfluorinated Chemical Species with a Combined Targeted and Non-Targeted-Screening High-Resolution Mass Spectrometry Workflow

“…Advances in SPE sample analysis using on-line setups greatly increase the throughput of the approach and improve the reproducibility of sample handling, but the fundamental process remains consistent 17 . Some efforts to remove the offline concentration of SPE using large volume injections have also been undertaken, but these require modifications to the chromatography that place them outside the realm of casual analysis 18,19 . Our sample analysis uses a polymeric weak anion exchange (WAX) retentive phase to thoroughly separate acidic PFAS materials from the traditional organic contaminants while achieving substantial sample concentration factors.…”