| A method for the determination of chlorinated hydrocarbons (CHCs) was developed. In this study, functionalized polysulfone membrane has been utilized as a sorbent for the extraction of CHCs in water samples. Two different functionalized polysulfones, (i) phosphonic acid functionalized polysulfone (PPSU-A) and (ii) phosphonic ester functionalized polysulfone (PPSU-E), both with cross-linked and non cross-linked subtypes, were evaluated for the extraction of CHCs in water. A 10 ml of spiked water sample was extracted with 50 mg 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, 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, type of polymer membrane as well as the nature of desorption solvent were optimized. Using optimum extraction conditions, calibration curves were linear with correlation of determination between 0.9954 and 0.9999 over the concentration range of 0.01 to 50 microg l-1. The method detection limits (at a signal-to-noise ratio of 3) were in the range of 0.4 to 3.9 ng l-1. The proposed method was evaluated for the determination of CHCs in drinking water samples.;A sensitive and accurate method for the determination of two acidic herbicides, 4-chloro- 2-methylphenoxy acetic acid (MCPA) and 4-chloro-2-methylphenoxy propanoic acid (MCPP), in water was explained. This method utilizes phase transfer catalyst-assisted cloud point extraction (CPE) for the preconcentration of the analytes simultaneously with derivatization. Factors affecting the performance of this method including pH of the aqueous matrix, temperature, extraction duration, type and amount of derivatization reagents and type and amount of the phase transfer catalyst (PTC) were investigated. Derivatization and PTC have proved especially vital to resolution of the analytes and their sensitive determination, with an advantage factor of 5.5-288 for catalyzed over noncatalyzed procedure. Within a wide range of concentrations (0.1-80 ng ml-1), the method displayed linearity (R2, 0.9911-0.9956). The low limits of detection for the two analytes (8.02 ng l-1 for MCPP and 30.04 ng l-1 for MCPA) would allow for the determination of these compounds of low concentrations in real samples. Negative matrix effect was eliminated through recovery calculations. Application of the method to real samples has revealed the presence of MCPP at concentrations between 0.27+/-0.01 and 0.84+/-0.06 ng ml -1.;A novel field sampling device based on porous membrane protected micro-solid phase extraction (micro-SPE) has been developed to determine 8 polycyclic aromatic hydrocarbons (PAHs). Acenaphthene, anthracene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene are classified as major pollutants by the US Environmental Protection Agency (EPA). This low cost device is the first field sampling device that utilizes a combination of sorbent material for onsite extraction of PAHs. It is easy to fabricate and offers many advantages over conventional field sampling techniques. In this procedure, PAHs were extracted onsite using this micro-SPE device. The small sized and reusable devices were then brought back to the laboratory for desorption followed by gas chromatography-mass spectrometric (GC-MS) analysis. The method detection limits for PAHs in sampled seawater ranged from 0.36 ng-1 -1 to 16.6 ng l-1. Calibration curves were linear over the concentration range of 0.05 to 10 microg l-1. The relative standard deviations (%RSD) were ≤ 5% (n=3) and the recoveries were between 95 and 107% for 0.05 microg l-1 spiked samples. These values were better than the ones obtained using conventional SPE methodology. Results for field deployment investigations confirmed the usefulness of the novel device for on-site analysis of PAHs. (Abstract shortened by UMI.)... |
