Speciation studies using hplc-icp-ms and hplc-es-ms

Bakırdere, Sezgin
Knowledge about selenium content of foods containing selenium species is very important in terms of both nutrition and toxicity. Bioavailability of selenium species for human body is different from each other. Hence, speciation of selenium is more important than total selenium determination. In the selenium speciation study, chicken breast samples, selenium supplement tablets and egg samples were analyzed for their selenium contents. In chicken breast study, chickens were randomly categorized into three groups including the control group (25 chickens), inorganic selenium fed group (25 chickens) and organic selenium fed group (25 chickens). After the optimization of all the analytical parameters used throughout the study, selenomethionine, selenocystine, Se(IV) and Se(VI) were determined using Cation Exchange-HPLC-ICP-MS system. In selenium supplement tablet study, anion and cation exchange chromatographies were used to determine selenium species. Arsenic is known as toxic element, and toxicity of inorganic arsenic species, As(III) and As(V), is much higher than organic arsenic species like arsenobetaine and arsenosugars. Hence, speciation of arsenic species in any matrix related with human health is very important. In the arsenic speciation study, Cation Exchange-HPLC-ICP-MS and Cation Exchange-HPLC-ES-MS systems were used to determine arsenobetaine content of DORM-2, DORM-3 and DOLT-4 as CRMs. All of the parameters in extraction, separation and detection steps were optimized. Standard addition method was applied to samples to eliminate or minimize the matrix interference. Thiols play an important role in metabolism and cellular homeostasis. Hence, determination of thiol compounds in biological matrices has been of interest by scientists. In the thiol study, Reverse Phase-HPLC-ICP-MS and Reverse Phase-HPLC-ES-MS systems were used for the separation and detection of thiols. For the thiol determination, thiols containing –S-S- bond were reduced using dithiothreitol (DTT). Reduction efficiencies for species of interest were found to be around 100%. Reduced and free thiols were derivatized before introduction on the column by p-hydroxymercuribenzoate (PHMB) and then separated from each other by using a C8 column. In the real sample measurement, yeast samples were analyzed using HPLC-ES-MS system.


Quality improvement in determination of chemical oxygen demand in samples considered difficult to analyze, through participation in proficiency-testing schemes
Raposo, F.; Fernandez-Cegri, V.; De la Rubia, M. A.; Borja, R.; Beltran, J.; Cavinato, C.; Clinckspoor, M.; Demirer, Göksel Niyazi; Diamadopoulos, E.; Frigon, J. C.; Koubova, J.; Launay, M.; Mendez, R.; Menin, G.; Noguerol, J.; Uellehdahl, H.; West, S. (Elsevier BV, 2010-10-01)
Chemical oxygen demand (COD) is a critical analytical parameter in waste and wastewater treatment, more specifically in anaerobic digestion, although little is known about the quality of measuring COD of anaerobic digestion samples. Proficiency testing (PT) is a powerful tool that can be used to test the performance achievable in the participants' laboratories, so we carried out a second PT of COD determination in samples considered "difficult" to analyze (i.e. solid samples and liquid samples with high con...
Use of Fourier transform infrared spectroscopy for rapid comparative analysis of Bacillus and Micrococcus isolates
Garip, Sebnem; Gözen, Ayşe Gül; Severcan, FERİDE (Elsevier BV, 2009-04-15)
The identification of foodborne microorganisms and their endospores in food products are important for food safety. The present work compares Bacillus (Bacillas licheniformis, Bacillus circulans and Bacillus silbtilis) and Micrococcus (Micrococcus luteus) species with Fourier transform infrared (FTIR) spectroscopy. Our results show that there are several characteristic peaks belonging to both the Micrococcus and Bacillus Species Which Call be used for the identification of these foodborne bacteria and their...
Current applications of exopolysaccharides from lactic acid bacteria in the development of food active edible packaging
Moradi, Mehran; Guimarães, Jonas T; Şahin, Serpil (Elsevier BV, 2021-08-01)
The lactic acid bacteria (LAB) are usually recognized as safe for consumption and comprise several genera with different technological and health-promoting potential for food applications, including probiotic characteristics. Their exopolysaccharides (EPS) have interesting film-forming properties and may be used to produce edible packaging, as a structural enhancer, a bioactive agent or probiotic carrier in edible films and coatings. In these days, there is a specific demand for food products with reduced a...
A biomechanical and spectroscopic study of bone from rats with selenium deficiency and toxicity
Turan, B; Bayari, S; Balcik, C; Severcan, Feride; Akkas, N (2000-06-01)
Selenium, being an essential mineral in the mammalian diet, is important in providing protection against oxidative damage. Numerous in vitro studies of selenium compounds reveal a very high correlation between catalytic activity of selenium compounds and toxicity. The present study was designed to investigate the effects of dietary selenium on the biomechanical properties of bone. New born rats of both sexes were fed with either a control, or a selenium- and vitamin E-deficient, or a selenium-excess and vit...
Studies on photochemical vapor generation of selenium
Çetmeli , Melis; Ertaş, Gülay; Department of Chemistry (2019)
Selenium is a significant trace element for human health. Selenium can be essential or toxic for human body depending on its concentration. Within the scope of this thesis, photochemical vapor generation tungsten coil atomization technique has been studied for the determination of selenium. Volatile selenium compounds were generated by exposure of UV light of the solution containing selenium and acetic acid. To increase sensitivity of photochemical vapor generation system, the technique was combined with tu...
Citation Formats
S. Bakırdere, “Speciation studies using hplc-icp-ms and hplc-es-ms,” Ph.D. - Doctoral Program, Middle East Technical University, 2009.