Sorption of As (V) from waters by use of novel amine-containing sorbents prior to HGAAS and ICP-MS determination

Thesis (Master)--İzmir Institute of Technology, Chemistry, İzmir, 2008Includes bibliographical references (leaves: 93-99)Text in English; Abstract: Turkish and Englishxiv 99 leavesA novel sorption method utilizing several amine-containing sorbents was developed for arsenic determination in waters by hydride generation atomic absorption spectrometry (HGAAS) and inductively coupled plasma mass spectrometry (ICP-MS).Chitosan, chitosan-immobilized sodium silicate, chitosan-modified macroporous silicate, and aminopropyl triethoxysilane-treated macroporous silicate were among the sorbents investigated for As(V) sorption.Sorption parameters were optimized for As(V) using chitosan and chitosanimmobilized sodium silicate and were then applied in all sorption studies. These parameters, namely, sorption pH, amount of sorbent, reaction temperature, and shaking time were 3.0, 50.0 mg, 25 .C, and 30 min, respectively. The sorption for chitosan under the optimized conditions was 89% (±1) while that for As(III) was lower than 10% at all pHs. In addition, chitosan-modified and amine-modified macroporous silicate demonstrated 88% (±3) and 68% (±12) sorption, respectively. After the sorption, the release of arsenate from chitosan and chitosan-immobilized sodium silicate was realized using two eluents; namely, 2.0% (v/v) acetic acid which dissolved chitosan, and 1.0% (w/v) L-cysteine solution having a pH of 3.0 adjusted with HCl which eluted arsenate by reducing to arsenite. Their respective desorption percentages were 90% (±1) and 100% (±4) for chitosan, and 67% (±2) and 100% (±1) for chitosan-immobilized sodium silicate.The preconcentration study performed using an absolute amount of 150.0 ng As(V) in bottled drinking water at the enrichment factors of 1, 2, and 10 has given 98% (±3), 95% (±2), and 78% (±4) recoveries, respectively. The accuracy of the proposed methodology with chitosan was verified with spike recovery tests for various water types at a concentration of 10.0 .g/L As(V). With matrix-matched calibration, the percentage spike recovery values were determined to be 114 (±4), 112 (±2), 43 (±4), and 0 (±1), for ultrapure, bottled, tap and sea water, respectively. These results have shown the strong suppression effect of the tap and the sea water matrixes

Development of a Carbon Mesh Supported Thin Film Microextraction Membrane As a Means to Lower the Detection Limits of Benchtop and Portable GC/MS Instrumentation

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.analchem.5b04008.In this work, a durable and easy to handle thin film microextraction (TFME) device is reported. The membrane is comprised of poly(divinylbenzene) (DVB) resin particles suspended in a high-density polydimethylsiloxane (PDMS) glue, which is spread onto a carbon fiber mesh. The currently presented membrane was shown to exhibit a substantially lesser amount of siloxane bleed during thermal desorption, while providing a statistically similar extraction efficiency toward a broad spectrum of analytes varying in polarity when compared to an unsupported DVB/PDMS membrane of similar shape and size which was prepared with previously published methods. With the use of hand-portable GC-TMS instrumentation, membranes cut with dimensions 40 mm long by 4.85 mm wide and 40 ± 5 μm thick (per side) were shown to extract 21.2, 19.8, 18.5, 18,4, 26.8, and 23.7 times the amount of 2,4 dichlorophenol, 2,4,6 trichlorophenol, phorate D10, fonofos, chloropyrifos, and parathion, respectively, within 15 min from a 10 ppb aqueous solution as compared to a 65 μm DVB/PDMS solid phase microextraction (SPME) fiber. A portable high volume desorption module prototype was also evaluated and shown to be appropriate for the desorption of analytes with a volatility equal to or lesser than benzene when employed in conjunction with TFME membranes. Indeed, the coupling of these TFME devices to hand-portable gas chromatography toroidial ion trap mass spectrometry (GC-TMS) instrumentation was shown to push detection limits for these pesticides down to the hundreds of ppt levels, nearing that which can be achieved with benchtop instrumentation. Where these membranes can also be coupled to benchtop instrumentation it is reasonable to assume that detection limits could be pushed down even further. As a final proof of the concept, the first ever, entirely on-site TFME-GC-TMS analysis was performed at a construction impacted lake. Results had indicated the presence of contaminants such as toluene, ethylbenzene, xylene, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, and tris(1-chloro-2-propyl)phosphate, which stood out from other naturally occurring compounds detected.the Natural Sciences and Engineering Research Council of Canada (NSERC

Sorption of As (V) from waters by use of novel amine-containing sorbents prior to HGAAS and ICP-MS determination

Thesis (Master)--İzmir Institute of Technology, Chemistry, İzmir, 2008Includes bibliographical references (leaves: 93-99)Text in English; Abstract: Turkish and Englishxiv 99 leavesA novel sorption method utilizing several amine-containing sorbents was developed for arsenic determination in waters by hydride generation atomic absorption spectrometry (HGAAS) and inductively coupled plasma mass spectrometry (ICP-MS).Chitosan, chitosan-immobilized sodium silicate, chitosan-modified macroporous silicate, and aminopropyl triethoxysilane-treated macroporous silicate were among the sorbents investigated for As(V) sorption.Sorption parameters were optimized for As(V) using chitosan and chitosanimmobilized sodium silicate and were then applied in all sorption studies. These parameters, namely, sorption pH, amount of sorbent, reaction temperature, and shaking time were 3.0, 50.0 mg, 25 .C, and 30 min, respectively. The sorption for chitosan under the optimized conditions was 89% (±1) while that for As(III) was lower than 10% at all pHs. In addition, chitosan-modified and amine-modified macroporous silicate demonstrated 88% (±3) and 68% (±12) sorption, respectively. After the sorption, the release of arsenate from chitosan and chitosan-immobilized sodium silicate was realized using two eluents; namely, 2.0% (v/v) acetic acid which dissolved chitosan, and 1.0% (w/v) L-cysteine solution having a pH of 3.0 adjusted with HCl which eluted arsenate by reducing to arsenite. Their respective desorption percentages were 90% (±1) and 100% (±4) for chitosan, and 67% (±2) and 100% (±1) for chitosan-immobilized sodium silicate.The preconcentration study performed using an absolute amount of 150.0 ng As(V) in bottled drinking water at the enrichment factors of 1, 2, and 10 has given 98% (±3), 95% (±2), and 78% (±4) recoveries, respectively. The accuracy of the proposed methodology with chitosan was verified with spike recovery tests for various water types at a concentration of 10.0 .g/L As(V). With matrix-matched calibration, the percentage spike recovery values were determined to be 114 (±4), 112 (±2), 43 (±4), and 0 (±1), for ultrapure, bottled, tap and sea water, respectively. These results have shown the strong suppression effect of the tap and the sea water matrixes

Biyo-yüzeylerden metabolomiks ve çoklu kalıntı analizleri için termal ve solvent desorpsiyonuna uygun esnek mikroekstraksiyon ince filmlerinin geliştirilmesi

Katı faz mikroekstraksiyon (solid phase microextraction, SPME) son zamanlarda örnekleme ve örnek hazırlama alanında sunduğu çözümlerle öne çıkmaktadır. SPME çok çeşitli şekillerde olabilir ve kolaylıkla numune hacmine, numune özelliğine ve çalışma türüne göre biçimlendirilebilir. SPME fiberleri özellikle in vivo klinik çalışmalarda invazif olmayan bir yöntem olduğu için tercih edilmektedir. Daha büyük bir ekstraksiyon fazına sahip ince film SPME ise yüksek duyarlılık gerektiren ölçümler için uygun bir alternatif oluşturmaktadır. İnce tabaka SPME kaplamaları çeşitli çalışmalarda kullanılmış olsa da aynı anda termal ve solvent desorpsiyonuna uygun olanları bulunmamaktadır. Böyle bir malzemenin en önemli avantajı ise tek bir örnekleme ile gaz ve sıvı kromatografik analizi mümkün kılması ve sonucunda çalışılan sistemden maksimum bilginin elde edilmesidir.Bu Proje biyo-yüzeylerden metabolomiks ve çoklu kalıntı analizleri için termal ve solvent desorpsiyonuna uygun esnek ve biyo-uyumlu mikroekstraksiyon ince filmlerinin geliştirilmesini hedeflemektedir. Bu çalışma ile ilk defa hidrofobik-lipofobik dengelenmiş polimer (HLB)-Teflon ve grafen-Teflon ince filmleri termal ve solvent dayanıklılığına sahip esnek destek üzerinde hazırlanacak ve hem gaz hem de sıvı kromatografisi ile elde edilebilecek bilgileri maksimize etmek için optimize edilecektir. Geliştirilecek bu malzemeler çeşitli alanlarda yüzeyden küçük molekül (‹1500 Da) tayinleri için analitik çözümler sunacaktır

Advancements in non-invasive biological surface sampling and emerging applications

Biological surfaces such as skin and ocular surface provide a plethora of information about the underlying biological activity of living organisms. However, they pose unique problems arising from their innate complexity, constant exposure of the surface to the surrounding elements, and the general requirement of any sampling method to be as minimally invasive as possible. Therefore, it is challenging but also rewarding to develop novel analytical tools that are suitable for in vivo and in situ sampling from biological surfaces. In this context, wearable extraction devices including passive samplers, extractive patches, and different microextraction technologies come forward as versatile, low-invasive, fast, and reliable sampling and sample preparation tools that are applicable for in vivo and in situ sampling. This review aims to address recent developments in non-invasive in vivo and in situ sampling methods from biological surfaces that introduce new ways and improve upon existing ones. Directions for the development of future technology and potential areas of applications such as clinical, bioanalytical, and doping analyses will also be discussed. These advancements include various types of passive samplers, hydrogels, and polydimethylsiloxane (PDMS) patches/microarrays, and other wearable extraction devices used mainly in skin sampling, among other novel techniques developed for ocular surface and oral tissue/fluid sampling

Thin-film microextraction coupled to LC-ESI-MS/MS for determination of quaternary ammonium compounds in water samples

The dual nature of the quaternary ammonium compounds, having permanently charged hydrophilic quaternary ammonium heads and long-chain hydrophobic tails, makes the sample preparation step and analysis of these compounds challenging. A high-throughput method based on thin-film solid-phase microextraction (SPME) and liquid chromatography mass spectrometry was developed for simultaneous quantitative analysis of nine benzylic and aliphatic quaternary ammonium compounds. Chromatographic separation and detection of analytes were obtained in reverse-phase mode in 8 min using a triple quadrupole mass spectrometer. Hydrophilic lipophilic balance particle-coated blades were found to be the most suitable among the different coatings tested in terms of recoveries and carryover on the blades. For desorption solvents, 70/30, v/v (A/B) with 0.1 % formic acid (where A is 10 mM ammonium acetate in acetonitrile/water (95/5, v/v) and B is 0.1 % (v/v) formic acid in isopropyl alcohol) was shown to be the most efficient solvent for the desorption of the analytes from the SPME sorbent. The SPME method was optimised in terms of extraction, pH, and preconditioning, as well as extraction and desorption times. Optimum conditions were 45 min of extraction time and 15 min of desorption time, all with agitation. The extraction was found to be optimum in a range of pH 6.0 to 8.0, which is consistent with the natural pH of water samples. Wide linear dynamic ranges with the developed method were obtained for each compound, enabling the application of the method for a wide range of concentrations. The developed method was validated according to the Food and Drug Administration criteria. The proposed method is the first SPME-based approach describing the applicability of the high-throughput thin-film SPME in a 96-well system for analysis of such challenging compounds