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Evaluation of analytical methods for the determination of free formaldehyde on textile substrate
Bojana Vončina, Alenka Majcen Le Marechal, Darinka Brodnjak-Vončina, 2007, original scientific article

Abstract: Release of formaldehyde from durable press-treated fabrics is a problem for human health and safety because formaldehyde is suspected to be carcinogenic. The accuracy of the standard test method for the free formaldehyde determination, Japan Law 112, depends on the formaldehyde content of the sample. The detection of low formaldehyde contents is particularly important in fields, like children clothing, so the application of high-performance liquid chromatography was evaluated. The results obtained by the standard testmethod, Japan Law 112, where UV/Vis spectrometer was used, were compared with the results obtained by HPLC method in which separation was performed on an RP C18 column with water-methanol as a mobile phase. It was shown that the detection limit and limit of quantification were improved using the HPLC method.
Keywords: analizna kemija, formaldehid, določevanje formaldehida, celulozna vlakna, HPLC, UV/VIS, analytical chemistry, formaldehyde, determination of formaldehyde, cellulose fibres, HPLC, UV/VIS
Published: 31.05.2012; Views: 1298; Downloads: 26
URL Full text (0,00 KB)

Sol-gel-based optical sensor for the detection of aqueous amines
Špela Korent Urek, Aleksandra Lobnik, Gerhard J. Mohr, 2007, original scientific article

Abstract: We present an optical sensor for the detection of aqueous amines obtained by incorporating chromoionophore XV (ETHT 4001) into sol-gel thin films. Acid- and base-catalyzed sol-gel processes were studied to prepare stable ormosil layers using various amounts of organically modified sol-gel precursor such asmethyltriethoxysilane (MTriEOS). The sensor layers were coated with a protective layer of microporous white polytetrafluoroethylene (PTFE) in order to prevent interference from ions and ambient light. The measurements were carried out in a flow-through cell in the reflection mode. Acid-catalyzed ormosil layers (pH 1) based on the copolymerization of tetraethoxysilane (TEOS) and MTriEOS did not show any change in signal upon exposure to aqueous amine solutions, while base-catalyzed sensor layers (pH 3 and 13) showed significant changes in signal. The response time (t100) for the base-catalyzedsensor layer L3 (pH 13) upon exposure to different solutions containing 0-608 mmol L-1 aqueous propylamine was 20-30 s, the regeneration time was 70 s and the detection limit was 0.1 mmol L-1. The sensor response was reproducible and reversible. The porous ormosil layers permit dry sensor storage conditions.
Keywords: analytical chemistry, optical sensors, sol-gel technology, determination of amines, fluorimetry
Published: 01.06.2012; Views: 1249; Downloads: 4
URL Full text (0,00 KB)

A facile lab scale synthesis of red selenium
Ebels Jörg, Stefan Spirk, Rudolf Pietschnig, 2006, published scientific conference contribution

Keywords: analytical chemistry
Published: 22.06.2017; Views: 84; Downloads: 4
.pdf Full text (327,78 KB)

NMR properties of SePPh3 in the solid state
Stefan Spirk, Rudolf Pietschnig, 2006, published scientific conference contribution

Keywords: analytical chemistry, isomers, stability, phosphorus
Published: 22.06.2017; Views: 90; Downloads: 3
.pdf Full text (330,10 KB)

Synthesis and structure of transition metal bisalkinylselenolato complexes
Rudolf Pietschnig, Carmen Moser, Stefan Spirk, Sven Schäfer, 2005, published scientific conference contribution

Abstract: We synthesized closely related cis and trans platinum complexes of SeCC-n-C5H11 and elucidated their structures in solution and the crystalline state. In line with previous work we find exclusive coordination of the selenium atom of the ambident alkynylselenolate ligand and a preference for the obviously more stable trans isomer. In contrast to previous work we find auniform increase of all metal ligand bond lengths in the cis vs. the trans isomers. Moreover we studied the coordination of alkynykselenolate ligands to group 4 metals.
Keywords: analytical chemistry, isomers, stability, metals
Published: 22.06.2017; Views: 85; Downloads: 12
.pdf Full text (614,73 KB)

Determination of penicillamine by batch and flow-injection potentiometry with AgI-based sensor
Njegomir Radić, Josipa Komljenović, Danilo Dobčnik, 2000, original scientific article

Abstract: Potentiometric determination of penicillamine (pen) is described based on a batch experiment and flow-injection analysis (FIA) using a chemical sensor with AgI-based membrane. The membrane was prepared by pressing silver salts (AgI, Ag2S) and powdered Teflon. This membrane was incorporated in a multipurpose electrode body for batch measurements, and in a tabular flow-through sensor body for FIA measurements. For batch measurements, the equilibrium potentials recorded with continuous addition of standard penicillamine solution were considered in relation to ▫$lg(c_pen/mol L^-1)$▫. Linear response with slope of 60 mV was obtained in the concentration range from 2.5 x ▫$10^5$▫ mol ▫$L^1$▫ to 1.8 x ▫$10^-2$▫mol ▫$L-1$▫. In using the tubular sensor with a membrane of the same coposition for FIA measurements, the linear response with slope of 59 mV was recorded in the concentration range from 1 x ▫$10^4$▫ mol ▫$L^1$▫ to 1 x ▫$10^-1$▫ mol ▫$L^-1$▫. The response of the applied chemical sensor to penicillamine (designated also as RSH) is explained by the formation of sparingly soluble RSAg in the reaction solution and/or the exposed surface of the sensor. The solubility product ▫$K_s(RSAg)$▫ was determined using experimental values recorded both by batch measurements and by the continuous-flow experiment. The mean value obtained by different measurements and using a membrane of the same composition is ▫$K_s(RSAg)$▫ = (1.4+-0.1) x ▫$10^-20$▫ mol ▫$L-2$▫).
Keywords: analytical chemistry, batch potentiometry, flow-injection analysis, membrane electrode, tubular sensors, penicillamine
Published: 05.07.2017; Views: 150; Downloads: 7
.pdf Full text (196,90 KB)

A silver/silver sulphide selective electrode prepared by means of chemical treatments of silver wire
Danilo Dobčnik, Igor Gros, Mitja Kolar, 1998, original scientific article

Abstract: The preparation and usability of a sulphide ion selective electrode, prepared by means of chemical pretreatment of silver wire with an ammonium perdisulphate solution, and the sulphidization in an alkaline sulphide solution are described. The electrode is suitable for direct potentiometric measuring of sulphide in alkaline solutions of concentrations down to ▫$1 X 10^{-6} mol/L$▫. The 45 min required for each chemical treatment are enough for the preparation of the described electrode.
Keywords: analytical chemistry, ion selective electrode, preparation, silver wire, potentiometric measurements, sulphide ions
Published: 17.08.2017; Views: 81; Downloads: 13
.pdf Full text (80,69 KB)

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