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Распространенность щелочных элементов Na, K, Li, Rb и Cs отличается в тысячи раз в природных образцах. Это одна из наиболее важных трудностей одновременного определения пяти щелочных элементов, которые обычно преодолевают, выполняя анализ одних и тех же проб несколькими аналитическими методами или методиками. Метод атомно-эмиссионной спектрометрии наиболее селективен для определения всех щелочных элементов в широких диапазонах их содержаний. Одновременное определение макро- и микросодержаний одной методикой экономически привлекательно для классификации пород, определении их возраста, реконструкции условий их образования или изменения в геологических процессах. Такие исследования требуют, чтобы полученные результаты анализа были надежны и достоверны. Благодаря использованию современного оборудования, была разработана методика одновременного определения пяти щелочных элементов методом атомно-эмиссионной спектрометрии. В настоящем исследовании оценены точность и правильность результатов разработанной методики. Особенностями методики являются получение и анализ высокосолевых растворов геохимических проб, использование низкотемпературного пропан-бутанового пламени для определения всех щелочных металлов, применение многоканальной фотоэлектрической регистрации спектров. Специфическая обработка данных обеспечивает учет спектрального фона и минимизацию матричных и спектральных помех при градуировке по стандартным образцам разнообразного состава и генезиса. Диапазоны определения содержаний ЩЭ в природных и техногенных средах расширены за счет улучшения их пределов обнаружения и использования нескольких аналитических линий на верхних границах определения Na, K и Rb. Сравнение результатов ПАЭС методики с результатами, полученными по методикам рентгенофлуоресцентной и масс-спектрометрии, а также методами стандартных добавок и разбавления, продемонстрировало их точность и правильность, удовлетворяющую требованиям геолого-геохимических исследований., One of the most important challenges in the simultaneous determination of the five alkaline elements is that their abundance differs thousands of times in natural samples. Therefore, usually the analysis of the same samples is performed using several analytical methods or techniques. An atomic emission spectrometry is the most selective method for the determination of alkaline elements in wide ranges of their contents. The reliable and correct simultaneous determination of major and trace elements contents by one method is economically attractive for classifying rocks, reconstructing the conditions of their formation, etc. The atomic emission spectrometry technique of the simultaneous determination of the five alkaline elements was developed with the use of the modern equipment. The accuracy and trueness of the developed technique results were evaluated in the current study. The technique features were the preparation and the analysis of the high-salt solutions of the geochemical samples, and the use of a low-temperature propane-butane flame and multichannel photoelectric recording of the spectra for the simultaneous determination of alkali metals contents. A specific data processing ensured accounting for the spectral background and minimizing the interferences when calibrating by CRMs with various compositions and genesis. The determined concentrations ranges of alkaline elements in natural and man-made environments had been expanded by improving the detection limits and using several analytical lines of Na, K and Rb with different spectral features. FAES results were compared with the results of XRF, ICP-MS, the standard addition and dilution methods, and its accuracy and trueness were found to be satisfactory for the requirements of geological and geochemical studies.

As short-chain chlorinated paraffins (SCCPs) are listed on several monitoring programs, validated methods are essential. However, their complexity and the lack of commercially available certified reference materials (RMs) hinder a proper validation of methods. Instead, one method is usually ‘validated’ by evaluating performances and results of spiked materials with that of one other method, which could easily lead to unreliable results. This study evaluated four analytical methods with different principles (i.e. comprehensive two dimensional GC coupled to a micro electron capture detector, developed for this study, chloride enhanced atmospheric pressure chemical ionization triple quadrupole time of flight MS (APCI-QToF-HRMS), GC coupled to an electron capture negative ion low resolution MS (GC–ECNI–LRMS) and carbon skeleton GC–MS), investigated the comparability in SCCP determination in spiked and naturally contaminated samples and determined SCCP amounts in candidate RMs for possible certification. The results cast doubt on the use of the most commonly applied method (i.e. GC–ECNI–LRMS), as well as using spiked materials for method validation. The APCI-QToF-HRMS method was found most promising as it achieves the required MS resolution (>21,000), is relatively fast and can detect also other CPs. The suitable identified SCCP levels in the candidate RMs and the agreement in results between the methods bring the first certification of a RM for SCCPs within reach.

As short-chain chlorinated paraffins (SCCPs) are listed on several monitoring programs, validated methods are essential. However, their complexity and the lack of commercially available certified reference materials (RMs) hinder a proper validation of methods. Instead, one method is usually ‘validated’ by evaluating performances and results of spiked materials with that of one other method, which could easily lead to unreliable results. This study evaluated four analytical methods with different principles (i.e. comprehensive two dimensional GC coupled to a micro electron capture detector, developed for this study, chloride enhanced atmospheric pressure chemical ionization triple quadrupole time of flight MS (APCI-QToF-HRMS), GC coupled to an electron capture negative ion low resolution MS (GC–ECNI–LRMS) and carbon skeleton GC–MS), investigated the comparability in SCCP determination in spiked and naturally contaminated samples and determined SCCP amounts in candidate RMs for possible certification. The results cast doubt on the use of the most commonly applied method (i.e. GC–ECNI–LRMS), as well as using spiked materials for method validation. The APCI-QToF-HRMS method was found most promising as it achieves the required MS resolution (>21,000), is relatively fast and can detect also other CPs. The suitable identified SCCP levels in the candidate RMs and the agreement in results between the methods bring the first certification of a RM for SCCPs within reach.

The methodology of sensory assessment (“panel test”) of virgin olive oil (VOO) is the sensory method included in international regulations and its application is compulsory in trading. Despite its application has been a success in authenticity of VOO quality, the application of panel test is not exempt of heated debates and controversies among olive oil actors that sometimes surpasses scientific arguments. Problems are consequence of some disagreements in the evaluation of the same VOOs from different testing laboratories, and today, there is a clamor for its enhancement from a considerable part of the industrial sector. The thin line that exists between the absence of sensory defects in extra-VOOs and a very slight sensory defect that may be perceived in some VOOs by some tasters is in the origin of the controversy. Thus, this work is focuses on providing practical solutions to the current concerns of Panel Test after analyzing proposals evaluating aroma descriptors from chemistry, examining flaws of panel test and strengthening its weak points. Practical Applications: The work describes a strategy that combines volatiles and sensory descriptors for avoiding disagreements with results provided by non-recognized testing laboratories, and proposes a blueprint for improving the process of training tasters with reference materials.

První kapitola disertační práce je věnována literární rešerši zaměřené na elektrotermické vypařování ve spojení s hmotnostní spektrometrií s ionizací v indukčně vázaném plazmatu (ETV-ICP-MS). Diskutovány jsou instrumentace, optimalizace pracovních podmínek, výhody a nevýhody této techniky a případové studie z literatury. Je zpracován přehled konkurenčních technik zavádění vzorku pro ICP-MS. Předložená disertační práce se ve své praktické části zabývá validací a testováním techniky ETV-ICP-MS. Tato technika je využita pro analýzu reálných vzorů životního prostředí a vzorků certifikovaných referenčních materiálů. Analytický výkon metody ETV-ICP-MS v analýze kapalných a suspenzních vzorků je porovnán s výkonem klasické ICP-MS roztokové analýzy s využitím zmlžovače a mlžné komory jako systému pro zavádění vzorku a s výkonem atomové absorpční spektrometrie s vysokým rozlišením, kontinuálním zdrojem záření a atomizací v grafitové kyvetě, umožňující dávkování pevných vzorků (SS-HR-CS-GFAAS). Následující část je věnována studii účinnosti transportu analytu v ETV-ICP-MS, s čímž souvisí použití chemických modifikátorů. Výstupem této studie je návrh a validace modifikátoru účinnosti transportu analytu pro ETV-ICP-MS založeném na uhlíkových mikročásticích, které slouží jako fyzické nosiče analytu. Na závěr je uživatelsky zhodnocena instrumentace elektrotermické vypařování ve spojení s hmotnostní spektrometrií s ionizací v indukčně vázaném plazmatu a průletovým analyzátorem s ortogonální akcelerací iontů (ETV-ICP-o-TOF-MS) od firmy GBC. Jednotka ETV GF 5000 byla zapůjčena na naše pracoviště za účelem jejího testování ve spojení s hmotnostním spektrometrem GBC Optimass 9500., The first chapter of this dissertation is devoted to the literature research focused on the inductively coupled plasma mass spectrometry connected to electrothermal vaporization (ETV-ICP-MS). An overview of available ETV-ICP-MS instrumentation is given. The optimization of the ETV-ICP-MS working conditions and suitable calibration strategies are discussed along with advantages and disadvantages of this technique. Recently published works regarding ETV-ICP-MS are mentioned. An overview of competing sample introduction techniques is given. In its practical part, the presented dissertation deals with the validation and testing of ETV-ICP-MS. This technique is used to analyse real environmental samples and samples of certified reference materials. The analytical performance of the ETV-ICP-MS method in the analysis of solutions and slurries is compared to the performance of the conventional ICP-MS method for solution analysis using a nebulizer and a spray chamber as the sample introduction system and to the performance of the solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (SS-HR-CS-GFAAS). The following part is devoted to the study of the analyte transport efficiency in ETV-ICP-MS, which is related to the use of chemical modifiers. The outcome of this study is the proposal and validation of the new analyte transport efficiency modifier for ETV-ICP-MS based on carbon microparticles acting as analyte carriers. The last part is devoted to the user evaluation of the inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry connected to the electrothermal vaporization (ETV-ICP-o-TOF-MS) instrumentation from the GBC Company. The ETV unit GF 5000 was borrowed to our workplace for testing purposes in the connection to the GBC Optimass 9500 mass spectrometer., Fakulta chemicko-technologická, Dokončená práce s úspěšnou obhajobou

The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: 40K, 210Pb (210Po), 226Ra, 228Ra, 228Th, 232Th, 234U, 238U, 239Pu, 239+240Pu and 241Am for IAEA-410 and 40K, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 228Th, 232Th, 235U, 238U, 239Pu, 240Pu and 239+240Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.

This work presents a microwave-based digestion method followed by a radiochemical extraction procedure to extract iodine from environmental matrices that provides iodine in a form suitable for the measurement of 129I by AMS, with shorter preparation times, small sample sizes and higher automation than previous methods. Samples were digested by a microwave digestion method in closed vessels using HNO3 as oxidizing agent. Following chemical iodine extraction consisted in an organic compound extraction followed by an aqueous solution extraction and iodine precipitation. Prepared samples were used to measure 127I by ICP-MS and 129I by AMS. The method was validated by ICP-MS measuring 127I content in standard reference materials covering a wide variety of biological, soil and sediment matrices: 1547 Peach Leaves, 1537a Tomato Leaves, 1549 Non-Fat Milk Powder, 2704 Buffalo River Sediment, 2711 Montana Soil and 1648 Urban Particulate Matter from the National Institute of Standards and Technology, IAEA-375 Soil and IAEA SL-1 Lake Sediment from the International Atomic Energy Agency and 186 Pig Kidney from Community Bureau of Reference. The recoveries with respect to the reference values were about 90%. Iodine losses during chemical extraction could be due to its volatilization as HI or I2 in acid means. Accurate results for determination in certified materials and good recoveries.

This work presents a microwave-based digestion method followed by a radiochemical extraction procedure to extract iodine from environmental matrices that provides iodine in a form suitable for the measurement of 129I by AMS, with shorter preparation times, small sample sizes and higher automation than previous methods. Samples were digested by a microwave digestion method in closed vessels using HNO3 as oxidizing agent. Following chemical iodine extraction consisted in an organic compound extraction followed by an aqueous solution extraction and iodine precipitation. Prepared samples were used to measure 127I by ICP-MS and 129I by AMS. The method was validated by ICP-MS measuring 127I content in standard reference materials covering a wide variety of biological, soil and sediment matrices: 1547 Peach Leaves, 1537a Tomato Leaves, 1549 Non-Fat Milk Powder, 2704 Buffalo River Sediment, 2711 Montana Soil and 1648 Urban Particulate Matter from the National Institute of Standards and Technology, IAEA-375 Soil and IAEA SL-1 Lake Sediment from the International Atomic Energy Agency and 186 Pig Kidney from Community Bureau of Reference. The recoveries with respect to the reference values were about 90%. Iodine losses during chemical extraction could be due to its volatilization as HI or I2 in acid means. Accurate results for determination in certified materials and good recoveries.

This work presents a microwave-based digestion method followed by a radiochemical extraction procedure to extract iodine from environmental matrices that provides iodine in a form suitable for the measurement of 129I by AMS, with shorter preparation times, small sample sizes and higher automation than previous methods. Samples were digested by a microwave digestion method in closed vessels using HNO3 as oxidizing agent. Following chemical iodine extraction consisted in an organic compound extraction followed by an aqueous solution extraction and iodine precipitation. Prepared samples were used to measure 127I by ICP-MS and 129I by AMS. The method was validated by ICP-MS measuring 127I content in standard reference materials covering a wide variety of biological, soil and sediment matrices: 1547 Peach Leaves, 1537a Tomato Leaves, 1549 Non-Fat Milk Powder, 2704 Buffalo River Sediment, 2711 Montana Soil and 1648 Urban Particulate Matter from the National Institute of Standards and Technology, IAEA-375 Soil and IAEA SL-1 Lake Sediment from the International Atomic Energy Agency and 186 Pig Kidney from Community Bureau of Reference. The recoveries with respect to the reference values were about 90%. Iodine losses during chemical extraction could be due to its volatilization as HI or I2 in acid means. Accurate results for determination in certified materials and good recoveries.

This work presents a microwave-based digestion method followed by a radiochemical extraction procedure to extract iodine from environmental matrices that provides iodine in a form suitable for the measurement of 129I by AMS, with shorter preparation times, small sample sizes and higher automation than previous methods. Samples were digested by a microwave digestion method in closed vessels using HNO3 as oxidizing agent. Following chemical iodine extraction consisted in an organic compound extraction followed by an aqueous solution extraction and iodine precipitation. Prepared samples were used to measure 127I by ICP-MS and 129I by AMS. The method was validated by ICP-MS measuring 127I content in standard reference materials covering a wide variety of biological, soil and sediment matrices: 1547 Peach Leaves, 1537a Tomato Leaves, 1549 Non-Fat Milk Powder, 2704 Buffalo River Sediment, 2711 Montana Soil and 1648 Urban Particulate Matter from the National Institute of Standards and Technology, IAEA-375 Soil and IAEA SL-1 Lake Sediment from the International Atomic Energy Agency and 186 Pig Kidney from Community Bureau of Reference. The recoveries with respect to the reference values were about 90%. Iodine losses during chemical extraction could be due to its volatilization as HI or I2 in acid means. Accurate results for determination in certified materials and good recoveries.

This work presents a microwave-based digestion method followed by a radiochemical extraction procedure to extract iodine from environmental matrices that provides iodine in a form suitable for the measurement of 129I by AMS, with shorter preparation times, small sample sizes and higher automation than previous methods. Samples were digested by a microwave digestion method in closed vessels using HNO3 as oxidizing agent. Following chemical iodine extraction consisted in an organic compound extraction followed by an aqueous solution extraction and iodine precipitation. Prepared samples were used to measure 127I by ICP-MS and 129I by AMS. The method was validated by ICP-MS measuring 127I content in standard reference materials covering a wide variety of biological, soil and sediment matrices: 1547 Peach Leaves, 1537a Tomato Leaves, 1549 Non-Fat Milk Powder, 2704 Buffalo River Sediment, 2711 Montana Soil and 1648 Urban Particulate Matter from the National Institute of Standards and Technology, IAEA-375 Soil and IAEA SL-1 Lake Sediment from the International Atomic Energy Agency and 186 Pig Kidney from Community Bureau of Reference. The recoveries with respect to the reference values were about 90%. Iodine losses during chemical extraction could be due to its volatilization as HI or I2 in acid means. Accurate results for determination in certified materials and good recoveries.

Pressurized liquid extraction with an integrated carbon trap (PLE-C) has recently been developed for fast and efficient analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in food and feed. The method has also been tested, but not verified, for use on more complex soil samples, such as soil, sediment and fly ash. Hence, the primary aim of this study was to verify that PLE-C can produce reliable data for PCDDs/PCDFs in various abiotic matrixes. A second aim was to find a replacement for the previously used AX21 active carbon that is currently not commercially available. The performance of the PLE-C was evaluated using both single congener concentrations and toxic equivalency potentials (TEQ-pot) of three (soil, sediment and fly ash) certified reference materials. The results clearly show that PLE-C can be used for abiotic samples and that a commercially available carbon (Norit SA 4PAH HF) can replace the AX-21 carbon in the carbon trap. The TEQ-pot values obtained for the soil and sediment samples were within the uncertainty limits of the corresponding certified values, as were the determinations of single congener concentrations. PLE-C therefore has great potential for determination of PCDDs/PCDFs in soil and sediment samples. The TEQ-pot result for the fly ash was slightly lower than the certified TEQ-pot value, but it is still within the uncertainty limits of the certified value. Out of the single congener concentrations all but four (out of 17) agreed well with the values. Hence, PLE-C may potentially be used also for fly ash-after slight modifications. The integrated PLE-C and cleanup procedure is less labour-intensive than traditional methods such as Soxhlet extraction followed by a multistep cleanup, and consumes smaller quantities of ultrapure solvents than the commonly used Power-Prep system. In addition, PLE-C is capable of larger sample throughputs than the conventional methods. Thus, PLE-C is a promising alterna

[EN] Seawater was sampled from different depths in the North Atlantic Ocean (Canary Islands region) and distributed among three different labs for the determination of titration alkalinity. Analysis was performed by potentiometric methods, involving titration in a closed cell, titration in an open cell and a two end-point acid addition method. The precision, which is the sample reproducibility taken from the mean standard deviation for replicate measurements, was between 0.45 and 0.90 µmol kg(-1) for the individual labs. Accuracy, here taken as the deviation for the values of a lab from the mean of all three, was mostly below 1 µmol kg(-1) and never exceeded 0.1% of the sample value. Mean standard deviation for all labs and all samples was 0.87 µmol kg(-1), once the individual methods were calibrated using certified reference material (CRM). Without CRM calibration, the mean standard deviation would increase to 2.8 µmol k(-1). The conclusion is that current high precision methods for alkalinity measurements calibrated with CRMs are able to reach similar accuracy as the measurement of total dissolved inorganic carbon by coulometry and therefore allow for the precise determination of the oceanic carbon dioxide system by using the two measured parameters., [ES] Se determinó la alcalinidad de muestras de agua de mar recogidas a diferentes profundidades en el Océano Atlántico Norte y distribuidas entre tres laboratorios, utilizando tres variantes potenciométricas: valoración en cubeta cerrada, valoración en cubeta abierta y un método de adición a doble punto final. La precisión, la reproducibilidad de la muestra obtenida a partir de la desviación estándar media para medidas replicadas, fue entre 0.45 y 0.90 µmol . kg(-1) para cada laboratorio. La exactitud, tomada como la desviación de los valores de un laboratorio respecto de la media de los tres, fue mayoritariamente menor que 1 µmol . kg(-1) y nunca excedió 0.1% del valor de la muestra. La desviación media estándar para todos los laboratorios y todas las muestras fue de 0.87 µmol . kg(-1), una vez que los métodos individuales se calibraron usando material certificado de referencia (CRM). Sin la calibración con CRM, la desviación estándar media se incrementaría a 2.8 µmol . kg(-1). Se concluye que la precisión real de los métodos para la medida de la alcalinidad calibrada con CRM es capaz de alcanzar exactitudes similares a las medidas de carbono inorgánico total por coulometría y por lo tanto permite la determinación precisa del sistema de carbono oceánico usando la medida de las dos variables.

The aim of this work was to evaluate current in-house HPLC procedures for the determination of naturally-occurring folates in food, and to identify problem areas for further improvement. Five intercomparison studies were completed over the period 1990-1997 in which nine participants from six countries took part. Through careful validations and detailed discussions held at evaluation meetings, possible biases and sources of systematic error have been identified and reduced. The use of ascorbic acid and nitrogen flushing during extraction, sample clean-up using strong anion exchange columns, spectrophometrically calibrated standards and fluorescence detection are all recommended. Both in-house hog kidney and human plasma deconjugase enzymes gave similar results to the circulated common hog kidney enzyme which was prepared from fresh pig's kidneys. The most consistently reported values were for 5-CH3H4-PteGlu, and to a lesser extent, for H(4)PteGlu. Four candidate reference materials (CRM 121, wholemeal flour; CRM 421, milk powder; CRM 485, lyophilised mixed vegetables, and CRM 487, lyophilised pig's liver) have been proposed with both indicative values (mean +/- uncertainty) for 5-CH3H4-PteGlu in CRM 421 (0.25; +/- 0.02 mg/kg) and CRM 485 (2.14; +/- 0.42 mg/kg), and information values (mean; range) for 5-CH3H4-PteGlu in CRh4 121 (0.04; 0.03-0.08 mg/kg) and CRM 487 (2.6; 1.9-3.8 mg/kg), Certified values are also given for total folate by microbiological assay: CRM 121 (0.50; +/- 0.07 mg/kg), CRM 421 (1.42; +/- 0.14 mg/kg), CRM 485 (3.15; 0.28 mg/kg), and CRM 487 (13.4; 1.3 mg/kg). Average recovery of 5-CH3H4-PteGlu, added prior to extraction and deconjugation, was 91% (84-95%) for the four CRMs. The average within- and between-laboratory variations were 6 and 15% for the determination of 5-CH3H4-PteGlu by HPLC, and 9 and 18% for the determination of total folate by microbiological assay. These CRMs will be used for quality control of folate measurements for nutritional