一种新型动力学被动采样技术—化学捕收器

化学捕收器（Chemcatcher）是一种新型可原位、连续、动态监测水环境污染物的被动采样技术。它以Fick扩散定律为定量基础,测定对象分为极性有机物、非极性有机物和无机物。本文介绍了该技术的装置组成、定量原理及其在水环境研究中的应用,并对此被动采样技术进行了评价与展望。     

Assessment of Chemcatcher passive sampler for the monitoring of inorganic mercury and organotin compounds in water

Abstract

Molecularly imprinted polymers (MIPs) for 4-nitrophenol have been successfully prepared by a thermal polymerization method using 4-vinylpyridine (4-VP) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker, respectively. The obtained materials were evaluated with respect to their selective recognition properties for 4-nitrophenol by HPLC using organic and aqueous eluents. Furthermore, the specific binding sites that have been created during the polymerization process were analyzed via radioligand binding assays. The successful imprinting against 4-nitrophenol provides a new opportunity for advanced separation materials used in environmental analysis.     

Mercury and organotin compounds monitoring in fresh and marine waters across Europe by Chemcatcher passive sampler

Several field trials have been carried out to assess the performance of the passive sampler Chemcatcher as aquatic monitoring technology for inorganic mercury and the organotin pollutants monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in different types of waters across ten locations in Europe. Two version of the sampler were used. One for mercury that consists on 47?mm Empore? disks of iminodiacetic chelating groups as the receiving phase overlaid by a diffusion membrane of polyethersulphone; and other for organotin compounds comprising a C₁₈ disk and a cellulose acetate membrane. Both membranes were held in a disposable polycarbonate body. The two samplers were calibrated in the laboratory in a previous work to estimate the pollutant concentration. For field sampling, the samplers were deployed for 14 days. In parallel spot samples were periodically collected during the deployment period for comparison purposes. No significant biofouling on the samplers was observed for the locations monitored. In general, water concentrations estimated by Chemcatcher were lower than those found in spot water samples due to the device only collected the soluble bioavailable fraction of target pollutants. However, the pre-concentration capability of Chemcatcher allowed the determination of the tested pollutants at levels where spot sampling fails, even in difficult water bodies such as sewage treatment plants. These advantages lead to consider this emerging methodology as a complementary tool to traditional spot sampling.     

Application of Chemcatcher passive sampler for monitoring levels of mercury in contaminated river water

A passive sampler (Chemcatcher) consisting of a 47 mm Empore™ chelating disk (CHE) with iminodiacetic groups as the receiving phase overlaid with a diffusion membrane was developed and calibrated for the monitoring of Hg in water. Three different diffusion membranes including cellulose acetate (CA), polyethersulphone (PS) and cellulose dialysis membrane (D) were tested. The best performance was obtained with the CHE-PS tandem. The effective sampling rate of the device (R_s, L day⁻¹) is defined as the equivalent volume of water extracted per unit time, and is analyte specific and can be determined experimentally in a flow-through tank. Effects of water temperature and turbulence on the uptake rate of Hg were assessed under controlled laboratory conditions. Sampling rates were in the range of 0.029-0.091 L day⁻¹. An increase in sampling rate with turbulence was demonstrated. The detection limit of the sampler obtained in flowing waters ranged between 2.2 and 2.9 ng L⁻¹ Hg. The performance of Chemcatcher was tested alongside spot water sampling in a 14-day field deployment at two locations on the Valdeazogues River, Almadén, Spain. In general, the Hg concentration estimated by the Chemcatcher was lower than that found in spot water samples collected over the same period. This may be explained by the behaviour of this sampler that measures only the labile fraction of Hg in water, and this will exclude some species. However, Chemcatcher preconcentrates Hg allowing its determination in some places where its concentration is below the detection limit of spot sampling.