A study of thin film solid phase microextraction methods for analysis of fluorinated benzoic acids in seawater

Abstract

Fluorinated benzoic acids (FBAs) are frequently used as tracers by the oil industry to characterize petroleum reservoirs. The demand for fast, reliable, robust, and sensitive approaches to separate and quantify FBAs in produced water, both in laboratory and field conditions, has not been yet fully satisfied. In this study, for the first time, thin film solid phase microextraction (TF-SPME) is proposed as a versatile sample preparation tool for the determination of FBAs in produced water by pursing two different approaches. First, an automated high throughput TF-SPME method using solvent desorption for fast and simultaneous preparation of multiple samples prior to liquid chromatographic separation and high resolution mass spectrometric detection (LC-MS) of FBAs was demonstrated for routine laboratory analysis. This method was optimized in terms of extraction phase chemistry, sample pH and ionic strength, extraction/desorption times using two representative FBAs (4-FBA and 2,3,4,5-tetra FBA). It incorporates a relatively simple sample pretreatment involving pH adjustment prior to the TF-SPME, and obtained limits of quantification (LOQ) are at the 1.0ngmL(-1) level. Second, the applicability of TF-SPME for fast mass spectrometric (MS) determination of FBAs with omission of derivatization and gas chromatographic (GC) separation was proven. This second method consists of manual extractions of analytes from seawater samples with a thermally stable TF-SPME membrane and direct thermal desorption of the extracted FBAs to a MS via a thermal desorption unit (TDU). It was demonstrated that the TF-SPME extracts and thermally releases analytes quantitatively and with good reproducibility. This approach opens up the possibility for on-site measurements with portable analyzers.

Development, Optimization and Applications of Thin Film Solid Phase Microextraction (TF-SPME) Devices for Thermal Desorption: A Comprehensive Review

“…There are various different approaches that can be employed toward the desorption of TF-SPME devices, and these techniques are chosen based on the characteristics of the compounds of interest and the composition of the TF-SPME device itself. Aside from TD, the second most common desorption method used for TF-SPME is liquid desorption (LD), commonly used in conjunction with liquid chromatography but also with various separation platforms [20][21][22][23]. LD utilizes an organic solvent (or a mixture of water and multiple organic solvents) to re-extract all compounds from the extraction phase before introduction of the now-analyte enriched liquid phase into an analytical instrument.…”

“…Since the advent of thermally stable extractive phases and binders, the TD of sorbents has been an attractive method for sample introduction to analytical instrumentation, as it requires no additional organic solvent as many other methods do [7][8][9]21]. As the science and engineering behind these thermally stable phases progress, the inherent background of newly developed phases (solid or liquid) is reduced, thus allowing the TD of appropriate sorbents to be applicable to ultra-trace level analysis [19,29,30].…”

“…Mohammadi et al demonstrated the use of a self-supported TF-SPME device composed of a zeolitic imidazolate framework, which extracts the organophosphorus pesticide ethion with subsequent TD for the analysis of environmental water samples [63]. In other respects, there are examples of more conventional TF-SPME being used in conjunction with LD for environmental analysis [64], ranging from the analysis of fluorinated benzoic acids in aqueous samples [21] to the analysis of polychlorinated biphenyls (PCBs) by direct application of a TF-SPME device into fish tissue [65].…”

Fast screening of illicit drugs in beverages and biological fluids by direct coupling of thin film microextraction to dielectric barrier discharge ionization-mass spectrometry

“…In previous studies, the PDMS/DVB TFME devices were directly interfaced to mass spectrometry (MS), through an electron ionization (EI) source using a single quadruple mass spectrometer. 5 The coupling was carried out by connecting a thermal desorption unit (TDU) to the mass spectrometer through a deactivated fused silica column. This approach employed a sample introduction system that involves two thermal desorption stages (the first to desorb the analytes from the TFME device, and the second to release the analytes into the chromatographic column) with a liquid nitrogen cryofocusing step in between, which yields narrow chromatographic peaks.…”

Investigation of 1-Dodecylimidazolinm Modified Filter Papers as a Thin-Film Microextraction Phase for the Preconcentration of Bisphenol A from Plant Oil Samples

“…This change in geometry can practically increase the extraction recovery of analytes without sacrificing the analysis time due to the large extraction phase surface area-to-volume ratio of the adsorption thin-films. 15,16 Some reported applications of TFME have been published in different matrixes, such as biological matrixes, 17 water, 15,[18][19][20][21] indoor air, 22 human exhaled breath condensates 23 and wine. 24 Filter paper, as 100% naturally derived cellulose nanofibers with a surface area of larger than 100 m 2 /g, 25 has been used as a platform in analytical and clinical chemistry because it is affordable, sustainable, hydrophilic, inert, and stable over a broad range of pH/ionic strengths.…”