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4. Mass fraction assignment of Amino Acids in acidic aqueous solution (CCQM-K78.a)

Author

Westwood, Steven, primary, Josephs, Ralf, additional, Choteau, Tiphaine, additional, Daireaux, Adeline, additional, Wielgosz, Robert, additional, Melanson, Jeremy, additional, Thibeault, Marie-Pier, additional, Meija, Juris, additional, Quan, Can, additional, Li, Hongmei, additional, Huang, Ting, additional, Zhang, Wei, additional, Song, Dewei, additional, Martos, Gustavo, additional, Delatour, Vincent, additional, Ohlendorf, Rüdiger, additional, Henrion, André, additional, Kakoulides, Elias, additional, Giannikopoulou, Panagiota, additional, Alexopoulos, Charalampos, additional, Chan, Kelly, additional, Lam, W H, additional, Fung, W H, additional, Yamazaki, Taichi, additional, Krylov, A, additional, Lopushanskaya, E, additional, Kharitonov, S, additional, Belyakov, M, additional, Sokolova, O, additional, Liu, Qinde, additional, Liu, Hong, additional, Yong, Sharon, additional, Prevoo-Franzsen, Déirée, additional, Fernandes-Whaley, Maria, additional, Kim, Byungjoo, additional, Jeong, Ji-Seon, additional, Kwon, Ha-Jeong, additional, Yang, Inchul, additional, Nammoonnoy, Jintana, additional, Ceyhan Gören, Ahmet, additional, Gündüz, Simay, additional, Ün, Ilker, additional, Bilsel, Gökhan, additional, Biesenbruch, Sabine, additional, and Lowenthal, Mark, additional

Published
2019
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5. Final report on key comparison CCQM-K55.c (L-(+)-Valine): Characterization of organic substances for chemical purity

Author

Westwood, Steven, primary, Josephs, Ralf, additional, Choteau, Tiphaine, additional, Daireaux, Adeline, additional, Wielgosz, Robert, additional, Davies, Stephen, additional, Moad, Michael, additional, Chan, Benjamin, additional, Muñoz, Amalia, additional, Conneely, Patrick, additional, Ricci, Marina, additional, Pires do Rego, Eliane Cristina, additional, Garrido, Bruno C, additional, Violante, Fernando G M, additional, Windust, Anthony, additional, Dai, Xinhua, additional, Huang, Ting, additional, Zhang, Wei, additional, Su, Fuhai, additional, Quan, Can, additional, Wang, Haifeng, additional, Lo, Man-fung, additional, Wong, Wai-fun, additional, Gantois, Fanny, additional, Lalerle, Béatrice, additional, Dorgerloh, Ute, additional, Koch, Matthias, additional, Klyk-Seitz, Urszula-Anna, additional, Pfeifer, Dietmar, additional, Philipp, Rosemarie, additional, Piechotta, Christian, additional, Recknagel, Sebastian, additional, Rothe, Robert, additional, Yamazaki, Taichi, additional, Zakaria, Osman Bin, additional, Castro, E, additional, Balderas, M, additional, González, N, additional, Salazar, C, additional, Regalado, L, additional, Valle, E, additional, Rodríguez, L, additional, Ángel Laguna, L, additional, Ramírez, P, additional, Avila, M, additional, Ibarra, J, additional, Valle, L, additional, Pérez, M, additional, Arce, M, additional, Mitani, Y, additional, Konopelko, L, additional, Krylov, A, additional, Lopushanskaya, E, additional, Lin, Teo Tang, additional, Liu, Qinde, additional, Kooi, Lee Tong, additional, Fernandes-Whaley, Maria, additional, Prevoo-Franzsen, Désirée, additional, Nhlapo, Nontete, additional, Visser, Ria, additional, Kim, Byungjoo, additional, Lee, Hwashim, additional, Kankaew, Pornhatai, additional, Pookrod, Preeyaporn, additional, Sudsiri, Nittaya, additional, Shearman, Kittiya, additional, Ceyhan Gören, Ahmet, additional, Bilsel, Gökhan, additional, Yilmaz, Hasibe, additional, Bilsel, Mine, additional, Çergel, Muhiddin, additional, Gonca Çoskun, Fatma, additional, Uysal, Emrah, additional, Gündüz, Simay, additional, Ün, Ilker, additional, Warren, John, additional, Bearden, Daniel W, additional, Bedner, Mary, additional, Duewer, David L, additional, Lang, Brian E, additional, Lippa, Katrice A, additional, Schantz, Michele M, additional, and Sieber, John R, additional

Published
2014
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6. Hava ve su örneklerinde organik bileşenlerin gaz kromatografisi ile belirlenmesi

Author

Bilsel, Gökhan, Oraltay, RGürcan, Fizik Anabilim Dalı, Oraltay, R. Gürcan, and Diğer

Subjects
Gas chromatography, Organik Bileşikler, Fizik ve Fizik Mühendisliği, Air, Organic compounds, Water, Physics and Physics Engineering, Air pollutants
Abstract

ÖZET Atmosferde bulunan ve elementel karbon, karbondioksit ve karbon monoksit dışındaki karbonlu bileşikler olarak tanımlanan uçucu organik bileşikler (UOB), hava kirleticilerin önemli bir sınıfını oluştururlar. Uçucu organik bileşiklerin çoğunun fotokimyasal duman oluşumunu başlatmak ve bazılarınında ozon tabakasının incelmesine neden olarak global ısınmaya katkıda bulunmak gibi insan sağlığına dolaylı etkilerinin yanısıra kansere yol açma gibi doğrudan etkileri de vardır. Özellikle benzen gibi mono aromatik ve pek çok poli aromatik hidrokarbonların kanser yapıcı özellikleri nedeniyle, ortam havasında saptama çalışmaları yapılmaktadır. Atmosferde bulunan uçucu organik bileşiklerin kontrolü için yaygın olarak kullanılan yöntem, bu bileşiklerin aktif karbon yada Tenax gibi katı adsorbantlar üzerinde tutulması ve tutulan bileşiklerin termal disorpsiyon ile kapiler kolona gönderilerek ayrılmasından sonra kütle spektrometresi dedektörlü gaz kromatografisi ile analiz edilmesidir. Bu tez çalışmasında, termal disorpsiyon ve ön-kolon soğutması geliştirilerek gaz kromatografisi - kütle spektrometresi cihazına bağlanarak kombine bir cihaz oluşturulmuştur. Bu cihaz sayesinde, çeşitli ortamlardan örneklediğimiz uçucu organik bileşiklerin yapılan aydınlatılabilmektedir. ABSTRACT Volatile organic compounds (VOCs), which are generally defined as any carbon containing compound found in the atmosphere except elemental carbon, carbon dioxide and carbon monoxide, are an important class of air pollutant. Many of the volatile organic compounds are precursors of photochemical smog pollution and some contribute to global warming by causing ozone depletion. In addition of these indirect mechanism, organic compounds may have direct effect on human health like inducing cancer. Exposure limits for many monoaromatic hydrocarbons, especially like benzen and many polyaromatic hydrocarbons are being tried to be lowered because of their carcinogenic effects. A widely used analytical method for the monitoring of volatile organic compounds in the atmosphere is sampling onto solid adsorbents (like activated carbon and Tenax ), and subsequent thermal desorption of trapped compounds on a capillary gas chromatic column and mass spectrometry. In this study, we have developed a Thermal Desorpsion and precoloumn cooling and made a complete system by joining it to the GC/MS. With this system, we were able to elucidate the structures of the VOCs sampled from the ambient air. Ill 73

Published
1998

13. Analysis of the Essential Oil Composition of Sideritis albiflora Using Direct Thermal Desorption and Headspace GC-MS Techniques.

Author

Topçu, Gülaçtı, Barla, Aslı, Gören, Ahmet C., Bİlsel, Gökhan, Bİlsel, Mine, and Tümen, Gülendam

Subjects
SIDERITIS, LAMIACEAE, PINENE, MENTHENONE, THERMAL desorption
Abstract

The main constituents of Sideritis albiflora were found to be trans-caryophyllene, a-pinene, b-pinene, g-cadinene pulegone, and caryophyllene oxide by both thermal desorption GC/MS and headspace GC/MS techniques. [ABSTRACT FROM AUTHOR]

Published
2005

14. Cytotoxic Activity and Essential Oil Composition of Leaves and Berries of Juniperus excelsa.

Author

Topçu, Gülaçtu, Gören, Ahmet C., Bilsel, Gökhan, Bilsel, Mine, Çakmak, Osman, Schilling, Jennifer, and Kingston, David G.I.

Subjects
JUNIPERS, ESSENTIAL oils, LEAVES, BERRIES, PLANT products, ANTINEOPLASTIC agents
Abstract

The composition of the water-distilled essential oils of the berries and leaves of Juniperus excelsa M. Bieb. were analyzed by gas chromatography-mass spectrometry (GC-MS). The main components in the berries of J. excelsa , accounting for 56.1% of the oil, were determined as a-pinene (34.0%), cedrol (12.3%), L-verbenol (5.4%), and D-verbenol (4.4%) while in the leaves of J. excelsa , accounting for 63.2% of the oil, were found to be a-pinen (29.7%), cedrol (25.3%), a-muurolene (4.4%), and 3-carene (3.8%). Cytotoxic and antimicrobial potential of the berries and leaves of J. excelsa were investigated. [ABSTRACT FROM AUTHOR]

Published
2005
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15. Analysis of the essential oil composition of Sideritis albiflora using direct thermal desorption and headspace GC-MS techniques

Author

Topçu, Gülaçtı, Barla, Aslı, Gören, Ahmet C., Bilsel, Gökhan, Bilsel, Mine, Tümen, Gülendam, Fen-Edebiyat Fakültesi, and Fen Edebiyat Fakültesi

Subjects
GC/MS, Sideritis Albiflora Hub.-Mor, Thermal Desorption, Headspace, Essential Oil
Abstract

Tümen, Gülendam (Balikesir Author), The main constituents of Sideritis albiflora were found to be trans-caryophyllene, alpha-pinene, beta-pinene, gamma-cadinene, pulegone, and caryophyllene oxide by both thermal desorption GC/MS and headspace GC/MS techniques.

17. Residual thiosulfate determination in omeprazole by liquid chromatography.

Author

Altun, Mehmet, Karakaş, Duran, and Bilsel, Gökhan

Subjects
*THIOSULFATES, *OMEPRAZOLE, *LIQUID chromatography, *HIGH performance liquid chromatography, *MOBILE phase (Chromatography)
Abstract

An HPLC-UV method for the determination of thiosulfate in aqueous media was modified and validated in this study to quantify the amount of residual thiosulfate in omeprazole samples. Absorption of thiosulfate ion was monitored at 215 nm in alcoholic tetrabutylammonium hydroxide solution as a mobile phase, in which the pH was adjusted to 6.20 by using dilute hydrochloric acid. A method detection limit of 0.08 mg/L was achieved for thiosulfate ion in 1000 mg/L omeprazole solution. The precision, accuracy, and the expanded uncertainty of the method were 2.7%, 92.4-102.6%, and 2.2% (at 95% confidence level (k = 2) assuming 1.0 mg/L thiosulfate in the sample solution), respectively. [ABSTRACT FROM AUTHOR]

Published
2016

18. Chemical Composition of Natural Colophony from Pinus Brutiaand Comparison with Synthetic Colophony

Author

Gören, Ahmet C., Bilsel, Gökhan, Öztürk, Alp Hakan, and Topçu, Gulaçtı

Abstract

The compositions of colophony resins obtained from Pinus brutiaTen trees by three different methods (acid paste, carved hole and scraping) from Ayvacık, Gökova and Kemalpaşa in Turkey were analyzed by capillary GC-MS. The main components were the monoterpenes α-pinene, β-pinene, and Δ3-carene, and the diterpenic resin acids palustric, abietic, kaur-9(11)-16-en-18-oic and neoabietic acid. The synthetic colophony resins exhibited similar contents to those of the natural resins obtained from the Gökova and Kemalpaşa regions of Turkey. However, colophony resins from Ayvacık exhibited only half the diterpenic acid content as those of the Gökova and Kemalpaşa resins. Out of the three techniques, the carved hole method caused rather different percentages in the constituents of the essential oils.

Published
2010
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19. Polyphenol Contents and Antioxidant Properties of Medlar (Mespilus germanica L.).

Author

Gülçin, İlhami, Topal, Fevzi, Sarıkaya, S. Beyza Öztürk, Bursal, Ercan, Bilsel, Gökhan, and Gören, Ahmet C.

Subjects
*MEDLARS (Plants), *PLANT extracts, *POLYPHENOLS, *ANTIOXIDANTS, *FLAVONOIDS, *HIGH performance liquid chromatography, *TANDEM mass spectrometry
Abstract

Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), N,N-dimethyl-p-phenylenediamine (DMPḊ+), and superoxide anion radicals (Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed.,) scavenging activity, hydrogen peroxide (H2O2), ferric ions (Fe3+) and cupric ions (Cu2+) reducing ability, Fe3+-TPTZ reducing ability, ferrous ions (Fe2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits. [ABSTRACT FROM AUTHOR]

Published
2011

20. Comparison of the Seed Oils of Ferulago trachycarpa Boiss. Different Localities with Respect to Fatty Acids.

Author

Erdemoğlu, Nurgün, Akalın, Emine, Akgöç, Mine, Çıkrıkçı, Simay, and Bilsel, Gökhan

Subjects
*FERULA, *FATTY acids, *COMPOSITION of seeds, *PLANT products, *CHEMICAL composition of plants, *PLANT chemical analysis, *BOTANICAL chemistry, GULF of Edremit (Turkey)
Abstract

The fatty acid composition of the seed oil of Ferulago trachycarpa Boiss., collected from two different localities (Balikesir-Edremit and Konya-Seydisehir), was analyzed for derived methyl esters of their fatty acids by capillary gas chromatography-mass spectrometry (GC-MS). Seventeen components representing 98.7 % of Balikesir sample and 98.6 % of Konya sample of F. trachycarpa seed oils were identified. GC-MS data showed that the main fatty acids were 9-octadeceneoic acid (68.1 and 73.6 %), 9,12-octadecadienoic acid (23.0 and 18.0 %), 9-hexadeceneoic acid (4.1 and 3.5 %) and 11-octadecenoic acid (2.0 and 1.8 %) in both oils, respectively. Unsaturated fatty acids were found as high as 97.7 and 97.4 %, while the percentage of the saturated fatty acids was found as low as 1.0 and 1.2 % in both seed oils, respectively. [ABSTRACT FROM AUTHOR]

Published
2008

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