Magnetic microsphere-based portable solid phase extraction device for on-site pre-concentration of organics from large-volume water samples

Highly Permeable Monolith-based Multichannel In-Tip Microextraction Apparatus for Simultaneous Field Sample Preparation of Pesticides and Heavy Metal Ions in Environmental Waters

A portable multichannel in-tip microextraction-based field sample preparation (FSP) apparatus was developed using polymer-based monoliths as an extraction phase. The construction of the FSP device is quite facile and convenient. More specifically, according to the chemical properties of studied analytes, functional-rich and high-permeability monoliths were in situ synthesized in pipet tips. After that, three tips containing the sorbents were mounted to three syringes, which were connected to a screw motor employed to drive the syringes and accurately regulate the flow rates in the adsorption and desorption stages. Because of the multifunction groups in the monoliths, the sorbents displayed satisfactory coextraction performance for pesticides (carbamates and triazoles) and heavy metal ions (Cd²⁺, Pb²⁺, and Cu²⁺) under the optimized conditions. The practicability of the proposed apparatus was demonstrated by the quick and simultaneous FSP of studied analytes in various environmental waters and combined with high-performance liquid chromatography/diode-array detection (for pesticides) and atomic absorption spectrometry (for metal ion) analysis. The results indicated that the limits of detection for the pesticides and metal ions were in the range of 0.36 to 1.2 ng/L and 0.061 to 0.40 ng/L, respectively, with ideal coefficients of determination. Furthermore, the results obtained with the constructed device were quite comparable to those obtained with the traditional laboratory extraction process, which demonstrated that the newly developed apparatus possesses the expected application in the high-throughput FSP of pesticides and heavy metal ions in water samples.

Pharmaceuticals and personal care products in the urban river across the megacity Shanghai: Occurrence, source apportionment and a snapshot of influence of rainfall

Occurrence of eleven pharmaceuticals and personal care products (PPCPs) along Huangpu River, a representative urban river of megacity Shanghai, was investigated in four sampling campaigns. The overall concentrations of PPCPs ranged from <LOQ to 1455 ng/L, and untreated domestic wastewater was proposed as an important source of PPCPs in Huangpu River. Higher contamination levels of target PPCPs were detected in the lower reach (urban area) and dry season, compared to those in the upper reach (rural area) and wet season, respectively. The influence of rainfall on the occurrence of PPCPs was also extensively discussed in different regions along Huangpu River. At sampling sites in the rural area, similar or even lower concentrations of PPCPs were detected after rainfall; while increased concentrations of PPCPs were observed at most sampling sites, especially in the urban area, suggesting that overflow of untreated wastewater exceeding the capacity of wastewater treatment plants and leachates generated at temporary storage and transfer station of solid wastes might be the additional sources of PPCPs in the urban area in rainy days. These findings indicated that management of wastewater or/and solid wastes was more important to solve the problem of PPCPs contamination in the urban river of megacity.

Ultrahigh selective adsorption of zwitterionic PPCPs both in the absence and presence of humic acid: Performance and mechanism

Since zwitterionic PPCPs could be combined with humic acid (HA) leading to certain contaminants residue in aqueous solution, adsorbents with much stronger binding with zwitterionic PPCPs were needed to avoid this phenomenon. Through comparison of serial magnetic carboxyl modified hypercrosslinked resins including MA10, MA30, MA40 and MA70, MA50 was found to exhibit ultrahigh selective adsorption of zwitterionic PPCPs including tetracycline and quinolone antibiotics due to the remarkable synergistic effects generated from cation exchange interaction and non-ion exchange interaction. To figure out the effect of HA, other five adsorbents including hypercrosslinked resin Q100, aminated hypercrosslinked resin GMA50, anion exchange resin MIEX, wood-based activated carbon F400D and coal-based activated carbon Norit were chosen as comparison to MA50 in adsorption performance of tetracycline (TC) and ciprofloxacin (CPX). It turned out that the percentage of CPX or TC combined with HA in aqueous solution varied greatly for studied adsorbents. There existed serious false-positive adsorption during the adsorption process by some commercial adsorbents such as MIEX and F400D, while MA50 exhibited relatively lower false-positive adsorption, ensuring the maximum safety of effluents. Breakthrough tests showed that MA50 had significant advantages in PPCPs removal at environment concentration, indicating its potential in application for real water.