Exploiting green sorbents in rotating‐disk sorptive extraction for the determination of parabens by high‐performance liquid chromatography with tandem electrospray ionization triple quadrupole mass spectrometry

Abstract

In this study, the viability of applying cork and montmorillonite clay modified with ionic liquid as biosorbents in the rotating-disk sorptive extraction technique was investigated. Specifically, this was aimed at the determination of methyl paraben, ethyl paraben, propyl paraben, and isobutyl paraben, with separation/determination by high-performance liquid chromatography coupled with mass spectrometry. The optimization of the method for both biosorbents was performed using multivariate procedures. The extraction efficiencies for the target compounds in aqueous matrices were compared to those obtained using the commercial sorbent Octadecil Silano-C18. The optimum extraction conditions for both natural sorbents were the use of an ammonia solution (pH 10) as desorption solvent and an extraction time of 30 min. The proposed methods show limits of quantification of 0.8 μg/L for cork, 3.0 μg/L for montmorillonite clay and 6.0 μg/L for Octadecil Silano-C18. The relative recoveries from river water and tap water samples ranged from 80.3 to 118.7% and 80.0 to 119.9% for cork and montmorillonite clay modified with ionic liquid, respectively. Relative standard deviations were obtained for intra- and interday precisions of <15% and <19% for cork and <19% and <17% for montmorillonite clay modified with ionic liquid.

Returning to Nature for the Design of Sorptive Phases in Solid-Phase Microextraction

“…In a recent study, the recovery results showed that the cork reaches higher sorption efficiency than C18, DVB, and nylon, and achieves very similar recoveries to those of Oasis ® HLB in which recoveries were between 67% and 98% for Oasis ® HLB, while the cork reached values between 63% and 89% [37]. In another study, on applying the optimized conditions for all sorbents, positive results were obtained for the cork-based methodology where using the same amount of sample and sorbent, the renewable sorbent provided better results when compared with the commercial C18 [34]. Therefore, cork proved to be an excellent alternative to the synthetic phases, presenting the advantage of achieving similar efficiency with a cost-effective benefit.…”

“…Regarding the recent publications, raw cork-based approaches have been highlighted in microextraction methodologies whereas they exhibit some unique analytical features that allow for "green", sustainable, and efficient procedures that are relevant to the current environmental concerns [30][31][32][33][34][35][36][37][38]. Table 1 points out the analytical features of the recent applications using raw cork-based methodologies for the extraction of different analytes from various matrices.…”

“…Afterward, the resulting powder is conditioned with acetonitrile, and it is ready to be applied as sorbent phase. Raw cork powder has been successfully applied in different microextraction approaches such as bar adsorptive microextraction [30,31], disposable pipette extraction [32,35,36], thin film-solid phase microextraction [33], and rotating disk sorptive extraction [34] as a biosorbent for the reliable determination of organic micropollutants, toxic metals, UV filters, endocrine disruptors, and compounds in aqueous samples as well as pharmaceuticals and lung cancer biomarkers in human urine. Cork exhibits significant hydrophobicity and a number of aromatic rings that can undergo effective π-π interactions with the analytes and substantially enhance the preconcentration ability of the extraction procedures.…”

Alternative Green Extraction Phases Applied to Microextraction Techniques for Organic Compound Determination

“…An eco-material denominated montmorillonite (MMT) clay, modified through the intercalation of ionic liquids (IL), has also been applied in the extraction phase [28,29]. MMT is a clay mineral composed of structural layers consisting of an octahedral alumina sheet sandwiched between two tetrahedral silica sheets.…”

“…Very recently, the viability of MMT-HDMIM-Br as a green sorbent for RDSE was again investigated [29]. In this study, cork and montmorillonite clay modified with ionic liquid were explored for the determination of parabens in water samples by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS).…”