WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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2002 - 200912010 - 20132

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Publisher: search.filters.publisher.Elsevier Ltd.Subject: search.filters.subject.Gas chromatography

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  • Article
    Citation - WoS: 4
    Citation - Scopus: 7
    Determination of Aluminum Rolling Oil Additives and Contaminants Using Infrared Spectroscopy Coupled With Genetic Algorithm Based Multivariate Calibration
    (Elsevier Ltd., 2010) Yalçın, Ayşegül; Ergün, Didem; İnanç Uçar, Özlem; Özdemir, Durmuş
    Genetic algorithm based multivariate calibration models were generated for infrared spectroscopic determination of aluminum rolling oil additives and contaminants such as gear and hydraulic oils. Two different additives and six different suspected contaminants were investigated in the base oil lubricant. Routine analysis samples from 9 different aluminum rolling systems were collected in a period of 2 months in an aluminum rolling plant and gas chromatography (GC) is used as the reference method. Infrared absorbance spectra of the samples were then collected and the reference values obtained with GC were used together with these spectra for model building. Inverse least squares method was optimized with a genetic algorithm by selecting the most contributing regions of the infrared spectra for each component. The R2 values between GC and multivariate spectroscopic determinations were around 0.99 indicating a good correlation between the two methods. Performance of genetic algorithm based multivariate calibration models were also compared with partial least squares (PLS) method. The study showed that infrared spectroscopy coupled with multivariate calibration can be used for continuous monitoring of additives and contaminants in aluminum rolling oil. By this way, analysis time is significantly reduced and simultaneous determination of all the components can be accomplished. © 2010 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 24
    Preparation and Characterization of Sodium Dodecyl Sulfate Doped Polypyrrole Solid Phase Micro Extraction Fiber and Its Application To Endocrine Disruptor Pesticide Analysis
    (Elsevier Ltd., 2013) Korba, Korcan; Pelit, Levent; Okçu Pelit, Füsun; Özdokur, K. Volkan; Ertaş, Hasan; Eroğlu, Ahmet Emin; Ertaş, Fatma Nil
    A robust in house solid-phase micro extraction (SPME) surface has been developed for the headspace (HS)-SPME determination of endocrine disruptor pesticides, namely, Chlorpyrifos, Penconazole, Procymidone, Bromopropylate and Lambda-Cyhalothrin in wine sample by using sodium dodecylsulfate doped polypyrrole SPME fiber. Pyrrole monomer was electrochemically polymerized on a stainless steel wire in laboratory conditions in virtue of diminishing the cost and enhancing the analyte retention on its surface to exert better selectivity and hence the developed polymerized surface could offer to analyst to exploit it as a fiber in headspace SPME analysis. The parameters, mainly, adsorption temperature and time, desorption temperature, stirring rate and salt amount were optimized to be as 70°C and 45min, 200°C, 600rpm and 10gL-1, respectively. Limit of detection was estimated in the range of 0.073-1.659ngmL-1 for the pesticides studied. The developed method was applied in to red wine sample with acceptable recovery values (92-107%) which were obtained for these selected pesticides.
  • Article
    Citation - WoS: 81
    Citation - Scopus: 102
    Effects of Equivalence Ratio on Species and Soot Concentrations in Premixed N-Heptane Flames
    (Elsevier Ltd., 2002) İnal, Fikret; Senkan, Selim M.
    The micro-structure of laminar premixed, atmospheric-pressure, fuel-rich flames of n-heptane/oxygen/argon has been studied at two equivalence ratios (C/O = 0.63 and C/O = 0.67). A heated quartz microprobe coupled to an online gas chromatography/mass spectrometry (HP 5890 Series II/HP 5972) has been used to establish the identities and absolute concentrations of stable major, minor, and trace species by the direct analysis of samples withdrawn from the flames. Benzene was the most abundant aromatic compound identified. The largest PAH detected were the family of C18H10 (molecular weight of 226) that include cyclopenta[cd]pyrene and benzo[ghi]fluoranthene, with peak concentrations reaching 8 ppm and 6 ppm, respectively. Soot particle diameters, number densities, and volume fractions were determined using classical light scattering and extinction measurements. The largest soot particle diameter measured was about 18 nm and the soot volume fraction reached the amount of 4.9 × 10-7.