Comparison of five integrative samplers in laboratory for the monitoring of indicator and dioxin-like polychlorinated biphenyls in water.

This study aimed at evaluating and comparing five integrative samplers for the monitoring of indicator and dioxin-like polychlorinated biphenyls (PCBs) in water: semi-permeable membrane device (SPMD), silicone rubber, low-density polyethylene (LDPE) strip, Chemcatcher and a continuous-flow integrative sampler (CFIS). These samplers were spiked with performance reference compounds (PRCs) and then simultaneously exposed under constant agitation and temperature in a 200 L stainless steel tank for periods ranging from one day to three months. A constant PCB concentration of about 1 ng·L(-1) was achieved by immersing a large amount of silicone rubber sheets ("dosing sheets") spiked with the target PCBs. The uptake of PCBs in the five samplers showed overall good repeatability and their accumulation was linear with time. The samplers SPMD, silicone rubber and LDPE strip were the most promising in terms of achieving low limits of quantification. Time-weighted average (TWA) concentrations of PCBs in water were estimated from uptake of PCBs using the sampling rates calculated from the release of PRCs. Except for Chemcatcher, a good agreement was found between the different samplers and TWA concentrations ranged between 0.4 and 2.8 times the nominal water concentration. Finally, the influence of calculation methods (sampler-water partition coefficients, selected PRCs, models) on final TWA concentrations was studied.

Polar organic chemical integrative sampler (POCIS): application for monitoring organic micropollutants in wastewater effluent and surface water.

In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of wastewater treatment plants. POCIS proved well adapted to sampling alkylphenols and several pharmaceuticals. Concentration factors and the decrease in limits of quantification, compared to grab water sample analyses, were significant except for hormones, ß-blockers and bronchodilators. Promising preliminary results obtained in situ on deuterated atenolol used as a performance reference compound need to be confirmed in-lab. This work confirms that POCIS is a valuable tool for monitoring hydrophilic organic molecules in river and wastewaters.

Evaluating the polar organic chemical integrative sampler for the monitoring of beta-blockers and hormones in wastewater treatment plant effluents and receiving surface waters.

Wastewater treatment plants (WWTP) are known to be a source of surface water contamination by organic compounds such as pharmaceuticals. The objective of the present work was to study the suitability of the polar organic chemical integrative sampler (POCIS) to monitor beta-blockers and hormones in effluents and surface waters. Four sampling campaigns were carried out in French rivers (the Saône, the Ardières, the Bourbre, and the Seine) between November 2007 and September 2008. Passive samplers were exposed in surface waters, upstream and downstream of WWTP outflows, and in effluents. Exposures lasted for up to 24 d to study the uptake kinetics directly in situ, and repeatability was assessed by exposure of triplicates. A good agreement was found between POCIS and water samples. With the exception of atenolol, beta-blockers showed a linear uptake during at least three weeks, and their sampling rates could be determined in situ. These sampling rates were then used to calculate time-weighted average concentrations of beta-blockers in the Seine River with an overall good accuracy and repeatability. Such calculations could not be performed for hormones because of their variable occurrences and low concentrations in water and POCIS. Polar organic chemical integrative sampler therefore seems to be a suitable tool for monitoring beta-blockers in surface waters impacted by WWTP effluents. Longer exposure durations would be necessary to determine the suitability of POCIS for monitoring hormones. Finally, preliminary assays on the use of several deuterated compounds as performance reference compounds showed promising results for deuterated atenolol.

Characterization of a new methylated Beta-cyclodextrin with a low degree of substitution by electrospray ionization mass spectrometry and liquid chromatography/mass spectrometry.

A new methylated beta-cyclodextrin (Me-beta-CD) with a low degree of substitution (DS) was characterized by electrospray ionization mass spectrometry (ESI-MS) and liquid chromatography coupled with ESI-MS (LC/ESI-MS). For ESI-MS analyses, the composition of the infused sample solution was optimized in order to obtain only singly charged ammoniated CDs without fragmentation. The DS value (i.e. the number of methyl groups per glucopyranose unit) was found to be 0.7, which was in accordance with the values previously obtained by other methods. The LC/ESI-MS analysis, derived from a method using evaporative light scattering detection, allowed the study of the substitution isomers of each derivative and appears to be an easy and rapid tool for the accurate characterization of Me-beta-CD mixtures.

Characterization of a new methylated beta-cyclodextrin with a low degree of substitution by matrix-assisted laser desorption/ionization mass spectrometry and liquid chromatography using evaporative light scattering detection.

A new methylated beta-cyclodextrin with a low degree of substitution was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and high-performance liquid chromatography (HPLC) with evaporative light scattering detection. Using alpha-cyano-4-hydroxycinnamic acid as the matrix and the thin layer method as the deposition procedure, MALDI-TOF-MS revealed that the mixture was composed of CDs bearing from 2 to 8 methyl groups with an average degree of substitution (DS) of 0.7 (i.e. 0.7 methyl groups per glucopyranose unit). Using a Purospher Star RP-18 endcapped column with acetonitrile-water mobile phase in gradient elution mode, HPLC was employed at analytical scale to obtain a chromatographic fingerprint of the crude mixture and at semi-preparative scale to fractionate it. MALDI-TOF-MS of these fractions revealed that the overall retention of the different derivatives, which depicts their polarity, was mainly driven by the DS and increased with the number of methyl groups on the CD moiety.

Liquid chromatography analysis of monosubstituted sulfobutyl ether-beta-cyclodextrin isomers on porous graphitic carbon.

The retention behaviour of the three positional isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was investigated on a porous graphitic carbon (PGC) column. The influence of the mobile phase composition (nature and concentration of organic and electronic modifiers) was studied as well as the effect of column temperature. These hydrophilic and anionic analytes were highly retained on the PGC stationary phase compared to octadecyl bonded phases. The retention is mainly governed by a reversed-phase mechanism with electronic interaction playing a secondary role. An increase in solute retention and efficiency with temperature was observed. Successful isocratic separation with satisfactory baseline resolution of the three isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was achieved at 75 degrees C on a Hypercarb column by using ammonium acetate as electronic modifier in water-acetonitrile (83:17). The chromatographic methodology developed can be easily used for relative quantification of each isomer within a mixture and can be applied for semi-preparative purification of each one. The evaporative light scattering detector allows the detection of these non UV-visible absorbing molecules.