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Determination of inorganic corrosion inhibitors by ion chromatography
Kapiasová, Anna ; Kubíčková, Anna (advisor) ; Kozlík, Petr (referee)
Corrosion inhibitors are substances that prevent the internal surface of the cooling system from corrosion. Inorganic corrosion inhibitors contain inorganic anions that passivate the surface, thereby preventing the diffusion of oxygen into the system and protecting the surface from oxidation. This study is aimed at the development and validation of a method for the determination of inorganic corrosion inhibitors (specifically chlorides, nitrites, nitrates, hydrogen phosphates, sulfates and molybdates) by ion chromatography. The optimal separation of anions was achieved with a mobile phase consist of 3.3 mM sodium carbonate and 3.3 mM sodium bicarbonate (pH= 10.1) at 45 řC using the column Metrosep A Supp 7 (250 × 4.0 mm with particle size of 5 µm) (Metrohm, Switzerland). Under these conditions the analysis took 48 minutes. After validation, the method was used to determine corrosion inhibitors in real coolant samples. The peaks of the individual anions contained in the coolants were verified by spiking with standards of anions. The anion concentrations were determined from the areas of these peaks using the calibration curves. Key words ion chromatography, engine coolants, corrosion inhibitors, inorganic ions
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Determination of bitrex using ultra-high performance liquid chromatography
Fuková, Kateřina ; Kubíčková, Anna (advisor) ; Křížek, Tomáš (referee)
In this work, a method for the determination of bitrex (denatonium benzoate) using ultra- high performance liquid chromatography was developed. A Kinetex C18 column (Phenomenex) with dimensions of 100×2.1 mm and a particle size of 1.7 μm was used for the determination. A mixture of acetonitrile with 0.1% formic acid (component A) and deionized water with 0.1% formic acid (component B) was used as the mobile phase. The best separation was achieved with the gradient program set: 0-2 min: 20 % → 70 % A (vol. %); 2- 3 min: 70 % A (vol. %); 3-3,5 min: 70 % → 20 % A (vol. %); 3,5-5 min: 20 % A (vol. %). The temperature of the column during the separation was 40 řC and flow rate was 0,3 ml/min. The developed method was partially validated. Repeatability was measured, the linearity of the method was verified for sample injection 1 μl and 5μl. For the same sample injection limit of detection and limit of quantification was determined. Using the developed method, seven real samples containing bitrex were measured. These samples differed in matrix. The samples were five different coolants, glass cleaner and a washing gel for black clothing. In coolant Carline Antifreeze G13 (producer OMA CZ) the concentration of bitrex was set at 23,4 ppm. In coolant CS Antifreeze G 13 (producer CLASSIC Oil) the concentration...
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Development of the electrophoretic method for determination of phosphates and borates in cooling mixtures
Listakhava, Iryna ; Křížek, Tomáš (advisor) ; Kubíčková, Anna (referee)
In this diploma thesis, a method of routine analysis of commercial coolants was developed, focused on the simultaneous determination of inorganic anions - phosphates and borates - as corrosion inhibitors in fresh mixtures and the markers of recycling quality. The method was developed for the instrumental technique of capillary zone electrophoresis with indirect detection at 254 nm. The following were optimized: background electrolyte (its composition, concentration, pH), measured samples (coolant dilution, suitable internal standard) and measurement conditions (capillary length, sample dosing). The influence of the sample matrix on the measurement results, the robustness of the calibration line (or the agreement of the response with the actual analyte concentration) and also the repeatability of the method were tested. Optimizations and tests resulted in a method based on a standard addition with the following parameters: background electrolyte of pH = 11.50 containing sodium chromate at 10 mmol l-1 concentration and CTAB at 1 mmol l-1 concentration; dilution of the coolant sample 20-50×, addition of internal standard MES at 0,1 mmol l-1 concentration, electrokinetic sample injection at -5 kV for 10 s, capillary length 50.0 cm, inner diameter 75 μm. The repeatability of the method expressed as a...
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Electrophoretic Determination of Tantalum in Recycled Coolants
Gogulin, Semen ; Křížek, Tomáš (advisor) ; Coufal, Pavel (referee)
This master thesis deals with the development of electrophoretic methods for determination of tantalum in recycled coolants used in the production of tantalum capacitors, as well as the separation of tantalum from chemically similar niobium. Developed methods are based on the formation of negatively charged complexes of tantalum and niobium with a number of ligands added to the separation electrolyte, especially tartaric and citric acid and 4-(2-pyridylazo)resorcinol. The separations were performed in a fused silica capillary of the inner diameter of 50 µm and the effective length of 36.5 cm, a negative voltage of -25 kV was applied to the capillary. Using a separation electrolyte containing 0.1 mol·l-1 of tartaric and citric acid at pH = 2, separation of niobium and tantalum was achieved in less than 3 minutes; the absorption spectrometric detection was carried out in the ultraviolet region at a wavelength of 200 nm, the detection limit was 2.8 ppm of tantalum, and the quantification limit was 9.2 ppm of tantalum. Addition of 4-(2-pyridylazo)resorcinol reduced the detection limit to 0.8 ppm of tantalum and the quantification limit to 2.6 ppm of tantalum; the electrolyte contained 0.1 mmol·l-1 of 4-(2-pyridylazo)resorcinol, 10 mmol·l-1 of tartaric acid, 10 mmol·l-1 of citric acid, and 25 mmol·l-1...
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Electrophoretical determination of corrosion inhibitors in engine coolants
Smrž, Dominik ; Kubíčková, Anna (advisor) ; Coufal, Pavel (referee)
A determination of corrosion inhibitors in engine coolants represent a difficult analytical problem due to their different physicochemical properties. Nowadays a lot of instrument methods are needed to determine them. The aim of this work was the development of methods for their determination using only one instrumentation. Capillary zone electrophoreses was chosen as a suitable technique. Three electrophoretic methods for three groups of corrosion inhibitors were developed. Firstly, method for determination of inorganic anions was developed in range from 5 to 50 ppm with limit of detection around 1 ppm. Background electrolyte contains sodium chromate, CTAB and CHES solution. Analytes were detected indirectly at 450 nm. Another method was for determination of organic acids anions. They were determined in range from 5 to 500 ppm. Limit of detection for each analyte was around 1 ppm. Measurement was made with PDC a CTAC water solution. Indirect detection was used for this determination at 350 nm. Last developed method can be use for determination of aryltrizoles in range from 5 to 500 ppm. Limit of detection was around 1 ppm. As a background electrolyte was used sodium tetraborate solution. The developed methods were validated and their suitability for determination of corrosion inhibitors in real...
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