Evaluation of the possibility of detecting benzenic pollutants by direct spectrophotometry on PDMS solid sorbent

Abstract

Solid-phase extraction has become one of the most commonly used techniques for preconcentration of analytes from environmental samples. In the standard use of solid sorbent phases the extracted pollutants are subsequently eluted with a suitable organic solvent before chromatographic analysis. An alternative to this procedure is analysis of the adsorbed and concentrated pollutants by direct application of a spectroscopic method (fluorimetry or absorptiometry) to the phase. Although this method cannot be expected to give results as precise as those given by chromatographic methods, it might have valuable applications, particularly for "on site" pollution monitoring. This paper reports an evaluation of the capability of the method for the spectrophotometric detection of BTX (benzene, toluene, xylenes) in aqueous media and in contaminated atmospheres, with polydimethylsiloxane (PDMS) as sorbent. The tests performed, with the estimated detection limits, indicate that the method is relatively simple and easy to operate and sensitive enough for application to the monitoring of pollution both in water and in air in an industrial ambient atmosphere.

On-line sensitive detection of aromatic vapor through PDMS/C3H7S-assisted SERS amplification

“…[30][31][32] To further improve the capability of the SERS substrate for immobilizing and detecting toluene vapor, a PDMS layer was employed to coat C 3 H 7 S-Au@Ag MLF. [30][31][32] To further improve the capability of the SERS substrate for immobilizing and detecting toluene vapor, a PDMS layer was employed to coat C 3 H 7 S-Au@Ag MLF.…”

“…As such, the detection limit of SERS could be down to the single molecule level. [25][26][27][28][29][30][31][32] Despite advance in enhanced SERS detection of weakly adsorbed molecules, most of the molecules captured by PDMS are still located far away from the hot spots of plasmonic substrates. thio, amino, nitrile, and nitro) that strongly chemisorb on the plasmonic metal surface.…”

Mesoporous silica films for sensing volatile organic compounds using attenuated total reflection spectroscopy

“…hydrophobicity to exclude the strong IR absorber water. This concept was proven on ATR crystals and optical fibers coated with polymers, [28][29][30] , mesoporous silica, 31,32 zeolites, 33,34 or metal oxides 35 to detect VOCs in gas or aqueous phase. While limits of detection (LODs) at the ppb-level for VOCs in aqueous phase and low ppm levels for the gas phase have been reached for polymer coatings, they lack in terms of adhesion to the ATR element and response time due to long diffusion times.…”

Design of exposed-core fiber for methadone monitoring in biological fluids

“…As an alternative approach, the detection and/or analysis of hydrophobic analyte from aqueous media has been performed via spectroscopic methods (absorptiometry or fluorimetry) directly applied on a solid sorbent phase (e.g. an appropriate polymer such as polydimethylsiloxane, PDMS) after extraction and pre-concentration [11,12], thus avoiding the use of organic solvents for elution and chromatography.…”