Calibration of Passive Samplers for the Monitoring of Pharmaceuticals in Water-Sampling Rate Variation

A passive sampler for synchronously measuring inorganic and organic pollutants in sediment porewater: Configuration and field application

In situ measurement of multiple pollutants coexisting in sediment porewater is an essential step in comprehensively assessing the bioavailability and risk of pollutants, but to date, this needs to be better developed. In this study, a passive sampler, consisting of an "I-shaped" supporting frame and inorganic/organic sampling units, incorporating equilibrium dialysis theory and kinetic/equilibrium sorption principle, was developed for the synchronous measurement of inorganic (e.g., phosphorus and metal(loid)s) and organic pollutants (e.g., parent and substituted PAHs). The equilibrium time and sampling rates were explored in laboratory tests to support in situ application. Profiles of pollutants in porewater within a vertical resolution of centimeters, i.e., 1 cm and 2 cm for inorganic and organic pollutants, respectively, were obtained by field deployment of the sampler for further estimation of diffusive fluxes across the sediment-water interface. The results suggested that the role of sediments for a specific pollutant may change (e.g., from "sink" to "source") during the sampling time. This study demonstrated the feasibility of synchronous measurement of inorganic and organic pollutants in sediment porewater by the passive sampler. In addition, it provided new insight for further investigation into the combined pollution effects of various pollutants in sediments.

Examining the applicability of polar organic chemical integrative sampler for long-term monitoring of groundwater contamination caused by currently used pesticides

The possibilities of expanding a groundwater quality monitoring scheme by passive sampling using polar organic chemical integrative sampler (POCIS) comprising HLB sorbent as the receiving phase were explored. Passive sampling and grab sampling were carried out simultaneously in the regions with vulnerable groundwater resources in Slovakia, between 2013 and 2021. For 27 pesticides and degradation products detected both in POCIS and the grab samples, in situ sampling rates were calculated and statistically evaluated. The limited effectiveness of the receiving phase in POCIS for sampling polar or ionized compounds was confirmed through a comparison of the medians of compound-specific sampling rates. For the majority of the monitored compounds the median sampling rates varied between 0.01 and 0.035 L/day. In some cases, the actual in situ values could be confirmed by parallel exposure of POCIS and silicone rubber sheet employed to obtain a benchmark for maximum attainable sampling rate. Sampling site and sampling period appear to have also some influence on the sampling rates, which was attributed in part to the groundwater velocity varying in both space and time. The influence of physico-chemical parameters (temperature, pH, electrolytic conductivity) remains mostly questionable due to the naturally limited ranges of recorded values over the entire duration of the study. Concentrations of pollutants in POCIS could be used for predicting time weighed average concentrations in water, provided the sampling rates were known and relatively constant. Generally, the compound-specific sampling rate cannot be considered constant due to a combination of naturally varying environmental factors that influence the actual in situ sampling rate. The relative standard deviation of concentration data from POCIS exposed in triplicates varied between approx. 5 %-50 %. Utilizing exploratory data analysis approach and tools enabled us to obtain a relatively complex picture of the situation and progress regarding pesticide pollution of groundwater in the monitored areas.

Development of a New Method to Estimate the Water Purification Efficiency of Bulk-Supported Nanosorbents under Realistic Conditions

The direct use of nanosorbents for water purification is limited due to their aggregation and the lack of techniques for their recovery from natural waters. To overcome these problems, the affixation of nanomaterials onto bulk, non-mobile supports has been proposed. However, a method to simulate the efficiency of these sorbents under realistic conditions is still not available. To address this need, this work describes a method for evaluating the sorption efficiency of nanosorbent materials incorporated on bulk supports under non-equilibrium conditions. The method combines the principles of passive sampling, an environmental monitoring technique that is based on passive diffusion of dissolved contaminants from water to a sorbent, with batch sorption experiments that measure sorption under equilibrium conditions, to determine the parameters associated with water purification. These parameters are the maximum sorption capacity of the sorbent and the sampling rate, which is the volume of contaminated water treated per unit of time. From these variables, the deployment time of the sorbent until reaching saturation is proposed as an alternative indicator of sorbent efficiency. As proof-of-principle, the removal of oxyanions from a Zr-metal-organic framework (MOR−1) immobilized on cotton textiles was investigated. The results show that the sorption capacity under passive diffusion uptake conditions, is approximately 20 mg/g for As(VI) and 36 mg/g Se(IV), which is 10 to 30 times lower compared to that determined in batch sorption studies, indicating that conventional equilibrium sorption overestimates the efficiency of the sorbents under realistic conditions. The application of the method to a worst-case scenario, involving the severe contamination of freshwaters with arsenate species, is also demonstrated.

Compounds of wastewater origin in remote upland lakes in Ireland

It is well established that persistent organic pollutants are transported long distances in the atmosphere and deposited into aquatic and terrestrial ecosystems in remote areas, including high altitude lakes. The objective of this research was to evaluate whether compounds of wastewater origin were present in four remote upland headwater lakes in Ireland that primarily receive loadings from atmospheric deposition. Using Polar Organic Chemical Integrative Samplers (POCIS) deployed in the lakes for 60 to 68 days, seven compounds were detected at levels that could be quantified but 25 of the target compounds were not detected. The detected compounds included the cannabinoid metabolite, tetrahydrocannabinol carboxylate (THC-COOH), codeine, acetaminophen (paracetamol), ibuprofen, and the artificial sweeteners, sucralose, and saccharin, which were all present at concentrations estimated to be < 125 ng/L. Caffeine was also present in the lakes at estimated concentrations between 213 and 1320 ng/L. Cocaine and tramadol were detected in POCIS deployed in some of the lakes, but at levels below the limits of quantitation. The highest concentrations of the target analytes were detected in two lakes located in the eastern part of Ireland. These data are consistent with regional atmospheric transport of these compounds originating from wastewater treatment plants in Ireland. However, contaminants from wastewater treatment plants in the United Kingdom may also be a source in these upland lakes that are located far from emissions of urban pollution.

In situ calibration of passive sampling methods for urban micropollutants using targeted multiresidue GC and LC screening systems

In this study, Chemcatcher^TM (CC) and Polar Organic Chemical Integrative Samplers (POCIS) passive samplers were chosen to investigate trace organic chemical residues in urban streams of the megacity of Sydney, Australia. In situ calibration with these passive samplers investigated 1392 organic chemicals. Six sets of CC passive samplers fitted with SDB-XC or SDB-RPS disks and six POCIS containing Oasis HLB sorbent were deployed at three sites. Every week for six weeks across three deployments, composite water samples were retrieved from autosamplers, along with one set of CC/POCIS passive samplers. Samples were analysed by Automated Identification and Quantification System (AIQS) GC/MS or LC/QTOF-MS database methods with 254 chemicals detected. The most frequently detected compounds under GC/MS analysis were aliphatic, pesticides, phenols, PAHs, sterols and fatty acid methyl esters while from LC/QTOF-MS analysis these were pesticides, pharmaceuticals, and personal care products. Sampling rates (R_s) ranged between <0.001 - 0.132 L day^-1 (CC SDB-XC, 18 chemicals), <0.001 - 0.291 L day^-1 (CC SDB-RPS, 28 chemicals), and <0.001 - 0.576 L day^-1 (POCIS Oasis HLB, 30 chemicals). Assessment of deployment duration indicated that about half of the chemicals that were continuously detected across all deployment weeks had maximal simple linear regression R² values at four weeks for CC SDB-RPS (seven of 13 chemicals) and at three weeks for POCIS Oasis HLB (seven of 14 chemicals). Where ranges of R_s recorded from the estuarine site were able to be compared to ranges of R_s from one or both freshwater sites, only tributyl phosphate had a higher range of R_s out of 21 possible chemical comparisons, and suggested salinity was an unlikely influence on R_s. Whereas relatively higher rainfall of the third round of deployment aligned with higher R_s across the estuarine and freshwater sites for CC SDB-RPS and POCIS for nearly all possible comparisons.

Development and application of a membrane assisted solvent extraction-molecularly imprinted polymer based passive sampler for monitoring of selected pharmaceuticals in surface water

In this work, we demonstrate the development, evaluation and pre-liminary application of a novel passive sampler for monitoring of selected pharmaceuticals in environmental waters. The samplers were calibrated in laboratory-based experiments to obtain sampling rates (Rs) for carbamazepine, methocarbamol, etilefrine, venlafaxine and nevirapine. Passive sampling was based on the diffusion of the target pharmaceuticals from surface water through a membrane bag which housed an ionic liquid as a green receiving solvent and a molecularly imprinted polymer. Effects of biofouling, deployment time and solvent type for the receiver phase were optimized for selective uptake of analytes in surface water. Notably, there was a decrease in the uptake of selected pharmaceuticals and consequently a decrease in their sampling rates in the presence of biofouling. The optimum matrix-matched sampling rates ranged from 0.0007 - 0.0018 L d^-1 whilst the method detection and quantification limits ranged from 2.45 - 3.26 ng L^-1 and 8.06 - 10.81 ng L^-1, respectively. The optimized passive sampler was deployed in a dam situated in the heart of a typical highly populated township in the Gauteng Province of South Africa. Only etilefrine and methocarbamol were detected and quantified at maximum time weighted average concentrations of 12.88 and 72.29 ng L^-1, respectively.

Carbon nanotube-passive samplers as novel tools for sampling and determining micropollutants in the aquatic environment

Passive sampling is an interesting and cost-effective strategy for the quantification of micropollutants in the aquatic environment. When combined especially with a sensitive analytical method such as liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS), the use of passive sampling devices (PSDs) enables long-term and reliable determination of a wide range of chemicals. In this study, carbon nanotubes (CNTs) were used as an innovative sorbent in POCIS-like samplers (Polar Organic Chemical Integrative Sampler). The developed CNTs-PSDs were calibrated by the flow-through method and the obtained sampling rates (R_s) of analytes were compared with the previously obtained R_s values using the semi-static method. Subsequently, passive samplers were placed in the Baltic Sea, the Nogat River, and the Sztumskie Pole Lake in order to sample and concentrate 28 chemical compounds belonging to the group of contaminants of emerging concern (CECs). For the first time, the effectiveness of the use of CNTs-PSDs in the field was proven by the quantification of carbamazepine, diclofenac, p-nitrophenol, bisphenol A, 3,5-dichlorophenol, 17-β-estradiol, 17-α-ethinylestradiol and metoprolol in the tested surface waters. The obtained time-weighted average (TWA) concentrations of analytes ranged from 0.22 ± 0.12 ng/L (for metoprolol in the Nogat River) to 32.1 ± 2.4 ng/L (for bisphenol A in the Sztumskie Pole Lake). More importantly, CNTs-PSDs determined a greater amount of micropollutants than grab sampling and solid-phase extraction (SPE), which proves the advantage of passive sampling over grab sampling, especially when monitoring contaminants in the aquatic environment at low concentration levels.

Calibration and field validation of POCIS passive samplers for tracking artificial sweeteners as indicators of municipal wastewater contamination in surface waters

Polar organic chemical integrative samplers (POCIS) are widely used to track contaminants in surface waters. However, POCIS have not been used previously to monitor for artificial sweeteners as an indicator of wastewater pollution. In this study, we report for the first time the POCIS sampling rates (Rs_cal) for four artificial sweetener compounds, acesulfame (0.001 L/day), sucralose (0.114 L/day), cyclamate (0.001 L/day), and saccharin (0.002 L/day). We also prepared a modified POCIS with Strata X-AW anion exchange resin as a sorbent (i.e., ax-POCIS) and determined the sampling rates for sucralose (0.060 L/day) and acesulfame (0.128 L/day). Rs_cal values were adjusted according to the rate of loss of the performance reference compound, metoprolol-d₆ from deployed POCIS to yield field sampling rates (i.e., Rs_field). Field validation of the monitoring method was conducted in Presqu'ile Bay on the north-central coast of Lake Ontario that is impacted by discharges from a sewage lagoon. POCIS were deployed at four sites within the bay and in the lagoon discharge. The four artificial sweeteners, as well as caffeine, ibuprofen, and other microcontaminants of sewage origin, were present throughout the bay at estimated concentrations in the ng/L range, and in the lagoon discharge at estimated concentrations higher by approximately one order of magnitude. Because acesulfame is present in ionic form over the pH range of natural waters, there are uncertainties related to the sampling rates using the standard POCIS. Sucralose is recommended as the best choice for source tracking using POCIS. There was good agreement between the concentrations of sucralose estimated from POCIS and the measured concentrations in grab samples of surface water in the bay. The present study provides key data for monitoring artificial sweeteners using POCIS.

Point or non-point source: Toxicity evaluation using m-POCIS and zebrafish embryos in municipal sewage treatment plants and urban waterways

Municipal sewage treatment plants (STPs) have been regarded as an important source of organic contaminants in aquatic environment. To assess the impact of STPs on occurrence and toxicity of STP-associated contaminants in receiving waterways, a novel passive sampler modified from polar organic chemical integrative sampler (m-POCIS) was deployed at the inlet and outlet of a STP and several upstream and downstream sites along a river receiving STP effluent in Guangzhou, China. Eighty-seven contaminants were analyzed in m-POCIS extracts, along with toxicity evaluation using zebrafish embryos. Polycyclic musks were the predominant contaminants in both STP and urban waterways, and antibiotics and current-use pesticides (e.g., neonicotinoids, fiproles) were also ubiquitous. The m-POCIS extracts from downstream sites caused significant deformity in embryos, yet the toxicity could not be explained by the measured contaminants, implying the presence of nontarget stressors. Sewage treatment process substantially reduced embryo deformity, chemical oxygen demand, and contamination levels of some contaminants; however, concentrations of neonicotinoids and fiproles increased after STP treatment, possibly due to the release of chemicals from perturbed sludge. Source identification showed that most of the contaminants found in urban waterways were originated from nonpoint runoff, while cosmetics factories and hospitals were likely point sources for musks and antibiotics, respectively. Although the observed embryo toxicity could not be well explained by target contaminants, the present study showed a promising future of using passive samplers to evaluate chemical occurrence and aquatic toxicity concurrently. Zebrafish embryo toxicity significantly decreased after sewage treatment, but higher toxicity was observed for downstream samples, demonstrating that urban runoff may produce detrimental effects to aquatic life, particularly in rainy season. These results highlight the relevance of monitoring nonpoint source pollution along with boosting municipal sewage treatment infrastructure.

Technical design and optimisation of polymer inclusion membranes (PIMs) for sample pre-treatment and passive sampling - A review

This review reports on the increasing interest in technical designs, calibration, and application of PIM-based devices in sample pre-treatment and passive sampling in environmental water monitoring from 2010 to 2021. With regards to passive sampling, devices are calibrated in a laboratory setup using either a dip-in or flow-through approach before environmental application. In sample preparation, the device set-ups can be offline, online or in a continuous flow separation device connected to a flow injection analysis system. The PIMs have also demonstrated potential in both these offline and online separations; however, there is still a draw-back of low diffusion coefficients obtained in these PIM set-ups. Electro-driven membrane (EME) extraction has demonstrated better performance as well as improved analyte flux. Critical in electro-driven membrane extraction is applying correct voltage that may not compromise the PIM performance due to leaching of components to the aqueous solutions. Further, besides different PIM configurations and designs being developed, PIM based extractions are central to PIM components (base polymer, carrier and plasticizer). As such, recent studies have also focused on improving PIM stability by investigating use of various PIM components, incorporating nano additives into the PIM composition, and investigating novel green PIM synthetic routes. All these aspects are covered in this review. Further, some recent studies that have demonstrated the ability to eliminate effects of flow patterns and membrane biofouling in PIM based applications are also included.

Development and application of an in-house library and workflow for gas chromatography-electron ionization-accurate-mass/high-resolution mass spectrometry screening of environmental samples

This work presents an optimized gas chromatography–electron ionization–high-resolution mass spectrometry (GC-EI-HRMS) screening method. Different method parameters affecting data processing with the Agilent Unknowns Analysis SureMass deconvolution software were optimized in order to achieve the best compromise between false positives and false negatives. To this end, an accurate-mass library of 26 model compounds was created. Then, five replicates of mussel extracts were spiked with a mixture of these 26 compounds at two concentration levels (10 and 100 ng/g dry weight in mussel, 50 and 500 ng/mL in extract) and injected in the GC-EI-HRMS system. The results of these experiments showed that accurate mass tolerance and pure weight factor (combination of reverse-forward library search) are the most critical factors. The validation of the developed method afforded screening detection limits in the 2.5–5 ng range for passive sampler extracts and 1–2 ng/g for mussel sample extracts, and limits of quantification in the 0.6–3.2 ng and 0.1–1.8 ng/g range, for the same type of samples, respectively, for 17 model analytes. Once the method was optimized, an accurate-mass HRMS library, containing retention indexes, with ca. 355 spectra of derivatized and non-derivatized compounds was generated. This library (freely available at https://doi.org/10.5281/zenodo.5647960), together with a modified Agilent Pesticides Library of over 800 compounds, was applied to the screening of passive samplers, both of polydimethylsiloxane and polar chemical integrative samplers (POCIS), and mussel samples collected in Galicia (NW Spain), where a total of 75 chemicals could be identified.

Comparative study of As (V) uptake in aqueous medium by a polymer inclusion membrane-based passive sampling device and two filamentous fungi (Aspergillus niger and Rhizopus sp.)

In this work a polymer inclusion membrane (PIM) is proposed as passive sampler material and compared with two filamentous fungi for As (V) uptake to evaluate its ability as chemical surrogate material for the monitoring of this metalloid in aquatic environments. Results show excellent passive sampling characteristics of the device since a linear uptake profile as a function of time was observed. The correlation coefficients between the PIM passive sampler with Aspergillus niger (r = 0.83) and Rhizopus sp. (r = 0.13) uptake, show that the first species is the best modeled by the PIM, suggesting its potential as a chemical substitute in bioavailability studies.

Passive Sampler Exchange Kinetics in Large and Small Water Volumes Under Mixed Rate Control by Sorbent and Water Boundary Layer

Exchange kinetics of organic compounds between passive samplers and water can be partly or completely controlled by transport in the sorbent. In such cases diffusion models are needed. A model is discussed that is based on a series of cosines (space) and exponentials (time). The model applies to mixed rate control by sorbent and water boundary layer under conditions of fixed aqueous concentrations (open systems, infinite water volumes, in situ sampling) and fixed amounts (closed systems, finite water volumes, ex situ sampling). Details on the implementation of the model in computational software and spreadsheet programs are discussed, including numerical accuracy. Key parameters are Biot number (ratio of internal/external transfer resistance) and sorbent/water phase ratio. Small Biot numbers are always indicative of rate control by the water boundary layer, but for large Biot numbers this may still be the case over short time scales. Application to environmental monitoring of nonpolar compounds showed that diffusion models are rarely needed for sampling with commonly used single-phase polymers. For determining sorption coefficients in batch incubations, the model demonstrated a profound effect of sorbent/water phase ratio on time to equilibrium. Application of the model to sampling of polar organic compounds by extraction disks with or without a membrane showed that moderate to major sorbent-controlled kinetics is likely to occur. This implies that the use of sampling rate models for such samplers needs to be reconsidered. Environ Toxicol Chem 2021;40:1241-1254. © 2021 SETAC.

Limitations of Integrative Passive Samplers as a Tool for the Quantification of Pharmaceuticals in the Environment - A Critical Review with the Latest Innovations

This review starts with a presentation of the theory of kinetic uptake by passive sampling (PS), which is traditionally used to distinguish between integrative and equilibrium samplers. Demonstrated limitations of this model for the passive sampling of pharmaceuticals from water were presented. Most notably, the contribution of the protective membrane in the resistance to mass transfer of lipophilic analytes and the well documented effect of external parameters on sampling rates contributed to the greatest uncertainty in PS application. The diffusion gradient in thin layer (DGT) technique seems to reduce the effect of external parameters (e.g., flow rate) to some degree. The laboratory-determined integrative uptake periods over defined sampler deployments was compared, and the discrepancy found suggests that the most popular Polar Organic Chemical Integrative Sampler (POCIS) could in some cases utilized as an equilibrium sampler. This assertion is supported by own calculations for three pharmaceuticals with extremely different lipophilic characters. Finally, the reasons performance reference compounds (PRCs) are not recommended for the reduction in uncertainty of the TWAC found by adsorptive samplers were presented. It was concluded that techniques of passive sampling of pharmaceuticals need a new uptake model to fit the current situation.

In situ calibration of polar organic chemical integrative sampler (POCIS) for monitoring of pharmaceuticals in surface waters

POCIS is the most widely applied passive sampler of polar organic substances, because it was one of the first commercially available samplers for that purpose on the market, but also for its applicability for a wide range of substances and conditions. Its main weakness is the variability of sampling performance with exposure conditions. In our study we took a pragmatic approach and performed in situ calibration for a set of 76 pharmaceuticals and their metabolites in five sampling campaigns in surface water, covering various temperature and flow conditions. In individual campaigns, R_S were calculated for up to 47 compounds ranging from 0.01 to 0.63 L d^-1, with the overall median value of 0.10 L d^-1. No clear changes of R_S with water temperature or discharge could be found for any of the investigated substances. The absence of correlation of experimental R_S with physical-chemical properties in combination with the lack of mechanistic understanding of compound uptake to POCIS implies that practical estimation of aqueous concentrations from uptake in POCIS depends on compound-specific experimental calibration data. Performance of POCIS was compared with grab sampling of water in seven field campaigns comprising multiple sampling sites, where sampling by both methods was done in parallel. The comparison showed that for 25 of 36 tested compounds more than 50% of POCIS-derived aqueous concentrations did not differ from median of grab sampling values more than by a factor of 2. Further, for 30 of 36 compounds, more than 80% of POCIS data did not differ from grab sampling data more than by a factor of 5. When accepting this level of accuracy, in situ derived sampling rates are sufficiently robust for application of POCIS for identification of spatial and temporal contamination trends in surface waters.

Sampling Rate of Polar Organic Chemical Integrative Sampler (POCIS): Influence Factors and Calibration Methods

As a passive sampling device, the polar organic chemical integrative sampler (POCIS) has the characteristics of simple operation, safety, and reliability for assessing the occurrence and risk of persistent and emerging trace organic pollutants. The POCIS, allowing for the determination of time-weighted average (TWA) concentration of polar organic chemicals, exhibits good application prospects in aquatic environments. Before deploying the device in water, the sampling rate (Rs), which is a key parameter for characterizing pollutant enrichment, should be determined and calibrated accurately. However, the Rs values strongly depend on experimental hydrodynamic conditions. This paper provides an overview of the current situation of the POCIS for environmental monitoring of organic pollutants in an aquatic system. The principle and theory of the POCIS are outlined. In particular, the effect factors such as the ambient conditions, pollutant properties, and device features on the Rs are analyzed in detail from aspects of impact dependence and mechanisms. The calibration methods of the Rs under laboratory and in situ conditions are summarized. This review offers supplementary information on comprehensive understanding of mechanism and application of the POCIS. Nevertheless, the Rs were impacted by a combined effect of solute–sorbent–membrane–solution, and the influence extent of each variable was still unclear. On this basis, the ongoing challenges are proposed for the future application of the POCIS in the actual environment, for instance, the need for this device to be improved in terms of quantitative methods for more accurate measurement of the Rs.

Assessment of metal/metalloid occurrence in rivers with their accumulation in macrophyte case study with Myriophyllum alterniflorum

Water quality monitoring with integrative tools is a main issue of concern for environment assessment. Submerged aquatic macrophyte can be a good candidate for the evaluation of contaminant content in rivers. Indeed, owing to their habitat, aquatic macrophytes interact directly with surface water; they can absorb contaminants and thus allow to detect their presence in water. In situ studies were conducted over 28 days in five aquatic environments, affected by different levels of anthropogenic pressure (domestic wastewater plant, industrial activities), during two field campaigns. We have investigated whether the accumulation of some metals and a metalloid (As) in Myriophyllum alterniflorum could be used to detect their occurrence in river waters. Our results demonstrated that long time bioaccumulation was correlated with the contaminant levels in water. However, the water composition and the duration of exposure affected the studied pollutants' absorption. On an operational point of view, the optimal duration of exposure of Myriophyllum alterniflorum to assess the water quality is conditioned by the contaminant contents in waters that can induce different defense mechanisms as the reduction of pollutant absorption and their efflux. In addition, the nutrient concentration influenced the accumulation of pollutants since the higher the nutrient level, the higher the essential metal accumulation was observed.

Influence of some physicochemical parameters on the passive sampling of copper (II) from aqueous medium using a polymer inclusion membrane device

Recently polymer inclusion membranes (PIMs) have been proposed as materials for passive sampling, nonetheless a theoretical base to describe the mass transfer process through those materials, under such conditions of monitoring, has not been elucidated. Under the assumption that: (i) the transport of the metal ion occurs at steady state conditions, (ii) the concentration gradients are linear, and (iii) the kinetics of the chemical reactions in the extraction process on the membrane are elemental; an equation for the passive sampling of copper (II) using a PIM system containing Kelex-100 as carrier is derived. The prediction capacity of this sampler under different conditions of temperature, metal concentration, flow velocity, ionic strength and pH is analyzed as well. Among the dependencies of the PIM on the physicochemical conditions, effects of concentration, temperature and flow velocity tend to increment copper (II) flux across the membrane, being the parameter temperature the one with the most pronounced effect at T ≥ 30 °C. Ionic strength had no great effect on passive sampler response, however the sampler is dependent on the acidity of the medium. The comparable metal ion concentrations estimated from the PIM sampler to those obtained by direct measurements of the sampling medium suggest that PIMs can be robust materials when used as passive sampler devices.

The Influence of Ionic Liquids on the Effectiveness of Analytical Methods Used in the Monitoring of Human and Veterinary Pharmaceuticals in Biological and Environmental Samples-Trends and Perspectives

Recent years have seen the increased utilization of ionic liquids (ILs) in the development and optimization of analytical methods. Their unique and eco-friendly properties and the ability to modify their structure allows them to be useful both at the sample preparation stage and at the separation stage of the analytes. The use of ILs for the analysis of pharmaceuticals seems particularly interesting because of their systematic delivery to the environment. Nowadays, they are commonly detected in many countries at very low concentration levels. However, due to their specific physiological activity, pharmaceuticals are responsible for bioaccumulation and toxic effects in aquatic and terrestrial ecosystems as well as possibly upsetting the body's equilibrium, leading to the dangerous phenomenon of drug resistance. This review will provide a comprehensive summary of the use of ILs in various sample preparation procedures and separation methods for the determination of pharmaceuticals in environmental and biological matrices based on liquid-based chromatography (LC, SFC, TLC), gas chromatography (GC) and electromigration techniques (e.g., capillary electrophoresis (CE)). Moreover, the advantages and disadvantages of ILs, which can appear during extraction and separation, will be presented and attention will be given to the criteria to be followed during the selection of ILs for specific applications.

Salinity and pH as factors affecting the passive sampling and extraction of pharmaceuticals from water

Passive sampling is an attractive technique for the long-term monitoring of pharmaceuticals in the water environment. The reliability of the received results depends on the properly performed calibration, namely the determination of analyte sampling rates. This step can be the source of a systematic error, as the sampling rate values are dependent on the water donor phase parameters. This is especially important for pharmaceuticals, since their chemical characteristics and ionic form change with pH. In this study, the cross-effect of pH (3, 7, and 9) and salinity (0, 7, and 35 practical salinity unit, using artificial sea water) on the passive sampling of 21 pharmaceuticals (antiparasitics, beta-blockers, non-steroidal anti-inflammatory drugs, sulfonamides) was tested. The primarily determined parameter was the sampling rate. In addition, the extraction efficiency, partitioning coefficient, and the concentration of the analytes on the sorbent were calculated. Generally, for the non-steroidal anti-inflammatory drugs, beta-blockers, and antiparasitics, the change both in pH and salinity had a negligible impact on the mentioned experimental parameters. In contrast, the extraction of sulfonamides was impacted by both pH and salinity, while lipophilicity was not a decisive parameter.

A Novel Active Sampler Coupling Osmotic Pump and Solid Phase Extraction for in Situ Sampling of Organic Pollutants in Surface Water

Active samplers for ambient monitoring of trace contaminants in surface water are highly desirable, but their use is often constrained by power supply. Here, we proposed a novel solution by coupling an improved osmotic pump (OP) with a solid-phase extraction (SPE) cartridge to construct a power-free active sampler for organic contaminants. The OP simply consisted of two cylindrical chambers separated by a reverse osmosis membrane. We, for the first time, added ion-exchange resins into the OP inlet chamber and successfully constructed OPs with a smooth and constant flow. In the OP-SPE sampler, water was continuously drawn through the SPE cartridge at a constant flow, and time-weighted average concentration over the sampling course may be easily calculated from the amount of target analytes retained on the SPE cartridge and water collected in the sampler. The OP-SPE samplers were deployed in a river to detect herbicides, and the measured concentrations were largely in agreement with the average of 11 daily spot samples. Given that a wide range of SPE cartridges are available for different classes of organic contaminants, this approach is versatile and may find widespread applications for in situ sampling of surface water under different conditions, including poorly accessible locations.

Selection of performance reference compound (PRC) for passive sampling of pharmaceutical residues in an effluent dominated river

A passive sampling device, a polar organic chemical integrative sampler (POCIS), was used to monitor 13 pharmaceuticals and 8 transformation products in upstream and downstream wastewater treatment plant effluent. A POCIS laboratory calibration study was performed to determine uptake behavior and the effect of water flow on the sampling rate. Most compounds showed a linear accumulation, and the sampling rate values ranged from 0.031 to 0.559 L/day. The developed POCIS samplers were used in field experiments in a wastewater-impacted river. Using the calculated sampling rates, the time-weighted average concentration values were measured by three different approaches: (1) laboratory calibration sampling rates (2) performance reference compound (PRC) correction sampling rates and (3) field calibration sampling rates. Nine deuterated compounds (acetaminophen-d₃, antipyrine-d₃, sulfamethoxazole-d₄, carbamazepine-d₁₀, diclofenac acid-d₄, clofibric acid-d₄, bezafibrate-d₆, ibuprofen-d₃ and naproxen-d₃) were studied as PRCs. Antipyrine-d₃ was successfully tested as a PRC for sulfamethoxazole, ibuprofen, 2-hydroxy ibuprofen, diclofenac acid, 4-hydroxydiclofenac acid, carbamazepin, carbamazepin 10,11-epoxide, sulfadiazine, 1-naphthol, antipyrine, naproxen and 4-chlorobenzoic acid. Finally, the POCIS was used to monitor target compounds in river water and measure their attenuation. For most compounds, the POCIS attenuation results were not significantly different from those of the spot samples, which demonstrated that a POCIS with a PRC correction can determine the attenuation of organic micropollutants in rivers.

Comparison of the sampling rates and partitioning behaviour of polar and non-polar contaminants in the polar organic chemical integrative sampler and a monophasic mixed polymer sampler for application as an equilibrium passive sampler

In this work, Oasis HLB® beads were embedded in a silicone matrix to make a single phase passive sampler with a higher affinity for polar and ionisable compounds than silicone alone. The applicability of this mixed polymer sampler (MPS) was investigated for 34 aquatic contaminants (log K_OW -0.03 to 6.26) in batch experiments. The influence of flow was investigated by comparing uptake under static and stirred conditions. The sampler characteristics of the MPS was assessed in terms of sampling rates (R_S) and sampler-water partition coefficients (K_SW), and these were compared to those of the polar organic chemical integrative sampler (POCIS) as a reference kinetic passive sampler. The MPS was characterized as an equilibrium sampler for both polar and non-polar compounds, with faster uptake rates and a shorter time to reach equilibrium than the POCIS. Water flow rate impacted sampling rates by up to a factor of 12 when comparing static and stirred conditions. In addition, the relative accumulation of compounds in the polyethersulfone (PES) membranes versus the inner Oasis HLB sorbent was compared for the POCIS, and ranged from <1% to 83% depending on the analyte properties. This is indicative of a potentially significant lag-phase for less polar compounds within POCIS. The findings of this study can be used to quantitatively describe the partitioning and kinetic behaviour of MPS and POCIS for a range of aquatic organic contaminants for application in field sampling.

Ionic liquids for the passive sampling of sulfonamides from water-applicability and selectivity study

Ionic liquids (ILs) are new-generation, non-volatile solvents which are designable, and their structure may be specifically adjusted to the current application needs. Therefore, it is possible to create and apply ILs which efficiently and selectively extract various analytes from different matrices. It has already been examined that ILs may be applied as receiving phases in passive sampling for the long-term water monitoring of PAHs and pharmaceuticals in water. In this paper, the concept of passive sampling with ILs (PASSIL applied as receiving phases) was continued and developed using phosphonium-, imidazolium-, and morpholinium-cation-based ILs. The target group of analytes was pharmaceuticals which represent one of the most common categories of water contaminants. Fourteen-day-long extractions using various ILs were performed in stirred conditions at a constant temperature (20 °C). The best extraction efficiency was achieved for trihexyl(tetradecyl)phosphonium dicyanamide ([P666-14][N(CN)₂]). For this preliminary calibration, the sampling rates were calculated for each sulfonamide. Once again, selectivity was observed in passive sampling using [P666-14][N(CN)₂]. Therefore, PASSIL is seen as a very promising method for pharmaceutical monitoring in water.