A novel on-site sample preparation approach for the organophosphorus pesticides (OPPs) using functional polymer-coated fibers with a portable agitation device has been developed and demonstrated. In this approach, a handheld battery-operated electric toothbrush was used to provide agitation of the sample solution at the sampling site to facilitate extraction. A functional conjugated polymer (2-(9,9-bis(6-bromo-2-ethylhexyl)9-H-fluoren-2-yl)benzene-1,4-diamine) was coated on commercial Technora fibers (each strand consisted of 1000 filaments, each of diameter ca. 9.23μm) which were then used for extraction. After extraction, the fibers were brought back to the laboratory in an icebox. The analytes were subsequently desorbed by organic solvent and the extract was analysed by gas chromatography-mass spectrometry. Six OPPs, triethylphosphorothiolate, thionazin, sulfotep, phorate, disulfoton and parathion were used as model compounds. Experimental parameters such as extraction time, desorption time, types of polymer fibers and fiber coatings as well the nature of desorption solvent were optimized in the laboratory prior to its on-site application of the procedure. Using optimum extraction conditions calibration curves were linear with correlation coefficient of 0.9748-0.9998 over the concentration range of 0.1-10μgl(-1). The method detection limits (at a signal-to-noise ratio of 3) were in the range of 0.3-30.3ngl(-1), which were lower than what could be achieved with solid-phase extraction performed at the laboratory. The proposed method was evaluated for the on-site extraction of OPPs in seawater samples.
"Also, many types of adsorbents e.g. C 18 bonded silica , nano-composite material , polymer-coated multi-fibers , sol-gel , activated soil filters , carbon nanotubes  and polyurethane foam  have been developed for the recovery of pesticides from aqueous media. Recently, solid-phase extraction has been applied widely to the analysis of environmental, food, biological, and pharmaceutical samples   . "
[Show abstract][Hide abstract] ABSTRACT: A new inexpensive sorbent (PUF-azo-Tan) was prepared by the coupling of tannic acid with polyurethane foam. PUF-azo-Tan was characterized using different tools. Two new bands at 1724.1 and 1596.8 cm−1 assigned for C&9552;O and N&9552;N groups are appeared in the IR spectrum of PUF-azo-Tan. The PUF-azo-Tan contains 0.95 and 0.15 mmol g−1 of phenolic and carboxylic groups, respectively. The pHZPC value of PUF-azo-Tan is 6.4. The PUF-azo-Tan has a considerable stability towards acid, alkali and organic solvents. Atrazine and prometryn pesticides were extracted and preconcentrate by PUF-azo-Tan column and then analyzed by gas chromatography (GC) coupled with mass spectrometry. The effects of different parameters including pH, sample volume, temperature, initial concentration of pesticides and shacking time were studied to optimize the presented procedure. The sorption capacity of PUF-azo-Tan was 0.14 mmol g−1 (32 m g g−1) and the extraction of the pesticides was accomplished within 3-5 minutes. Kinetics studies data fitted the pseudo-second-order model (R2 = 0.989). The average detection limit of triazine pesticides in solution was 0.6 ng mL−1 (RSD = 0.35%, n = 3). The equilibrium process was well described by the Freundlich isotherm model (R2 = 0.993). The extraction of the tested pesticides was accomplished in a period range 3-5 minutes. The proposal study reveals PUF-azo-Tan has the potential of application as an efficient sorbent for the extraction and preconcentration of pesticides in cucumber, guava and potato foods, and water samples.
[Show abstract][Hide abstract] ABSTRACT: On-site sampling and sample preparation favor portable, solventless or even solvent-free techniques. Solid-phase microextraction (SPME) has these advantages. This review focuses on developments between 2007 and early 2011 in microextraction techniques for on-site sampling and sample preparation, including fiber SPME, stir-bar sorptive extraction (SBSE), thin-film microextraction (TFME) and different types of in-needle SPME. The major trends in on-site applications of SPME appear to be fiber and thin-film SPME, microextraction by packed sorbent (MEPS) and the sorbent-packed needle-trap device (NTD). We discuss and compare several aspects of these types of SPME in on-site applications. We also describe sorbent phases for SPME that benefit on-site applications. Finally, we provide a perspective on SPME-based techniques for on-site applications.
[Show abstract][Hide abstract] ABSTRACT: In this study, functionalized polysulfone membrane has been utilized as a sorbent for the extraction of chlorinated hydrocarbons (CHCs) in water samples. Two different functionalized polysulfones (i) phosphonic acid functionalized polysulfone (PPSU-A) with different forms (cross-linked and non cross-linked) membranes and (ii) phosphonic ester functionalized polysulfone (PPSU-E) with different forms (cross-linked and non cross-linked) were evaluated for the extraction of CHCs in water. A 10 ml of spiked water sample was extracted with 50mg piece of the functionalized membrane. After extraction, the membrane was desorbed by organic solvent and the extract was analyzed by gas chromatography-mass spectrometry. Eight CHCs, 1,3,5-trichlorobenzene (1,3,5-TCB), 1,2,3-trichlorobenzene (1,2,3-TCB), 1,1,2,3,4,4-hexachloro-1,3-butadiene (HCBD), 1,2,4-trichloro-3-methylbenzene (TCMB), 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB), pentachlorobenzene (PeCB) and hexachlorobenzene (HCB) were used as model compounds. Experimental parameters such as extraction time, desorption time, types of polymer membrane as well the nature of desorption solvent were optimized. Using optimum extraction conditions calibration curves were linear with coefficients of determination between 0.9954 and 0.9999 over wide range of concentrations (0.05-100 μgl(-1)). The method detection limits (at a signal-to-noise ratio of 3) were in the range of 0.4-3.9 ng l(-1). The proposed method was evaluated for the determination of CHCs in drinking water samples.
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