Novel on-site sample preparation approach with a portable agitator using functional polymer-coated multi-fibers for the microextraction of organophosphorus pesticides in seawater.
ABSTRACT 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.
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ABSTRACT: In this work, a new type of sorbent (polyhydroxyl-polyurethane foam or PPF) was synthesized by using water hydrolysis of polyurethanediazonium chloride salt. PPF was characterized using different tools (infrared spectra, elemental analysis, scanning electron microscopy and thermogravimetric analysis). It was tested for the extraction of atrazine, prometryn and terbutryn herbicides from environmental samples. The batch technique was conducted to evaluate the effects of initial pH, contact time, temperature, volume of sample and initial concentration of triazine herbicides on the removal of the herbicides from the aqueous solution. The extraction of the herbicides was accomplished in a period ranging from 5-15 min. The experimental data of the sorption was fitted by pseudo-first and pseudo-second-order kinetic mathematical equations and better followed the pseudo-second-order kinetics (R(2) ≈ 0.966). The equilibrium process was accurately described by the Freundlich isotherm model; the average Freundlich constant (1/n) value was 0.68, which was attributed to the heterogeneous surface structure of the PPF. The average capacity of the conventional polyurethane foam material was 0.34 mmol/g for herbicides. The study shows that PPF has the potential to be applied as an efficient sorbent for the extraction of herbicides from real matrix samples.Journal of chromatographic science 12/2012; · 0.79 Impact Factor
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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.Talanta 12/2011; 87:284-9. · 3.50 Impact Factor
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ABSTRACT: A novel solid phase microextraction (SPME) fiber was prepared and coupled with gas chromatography corona discharge ion mobility spectrometry (GC-CD-IMS) based on polypyrrole/montmorillonite nanocomposites for the simultaneous determination of diazinon and fenthion. The nanocomposite polymer was coated using a three-electrode electrochemical system and directly deposited on a Ni-Cr wire by applying a constant potential. The scanning electron microscopy images revealed that the new fiber exhibited a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The effects of different parameters influencing the extraction efficiency such as extraction temperature and time, salt addition, stirring rate, the amount of nanoclay, and desorption temperature were investigated and optimized. The method was exhaustively evaluated in terms of sensitivity, recovery, and reproducibility. The linearity ranges of 0.05-10 and 0.08-10μgL(-1), and the detection limits of 0.020 and 0.035μgL(-1) were obtained for diazinon and fenthion, respectively. The relative standard deviation values were calculated to be lower than 5% and 8% for intra-day and inter-day, respectively. Finally, the developed method was applied to determine the diazinon and fenthion (as model compounds) in cucumber, lettuce, apple, tap and river water samples. The satisfactory recoveries revealed the capability of the two-dimensional separation technique (retention time in GC and drift time in IMS) for the analysis of complex matrices extracted by SPME.Analytica chimica acta 03/2014; 814C:69-78. · 4.31 Impact Factor