Perspectives and challenges of on-site quantification of organic pollutants in soils using solid-phase microextraction

This study explores the current state-of-the-art progress toward on-site quantification of organic pollutants in soils with solid-phase microextraction (SPME). In spite of many available methods, only few publications report on-site analyses of soil samples by SPME. To date, the only application of SPME for the on-site quantification of organic pollutants in soil has been devoted to trichloroethylene. The problem of matrix effects limiting quantification by external standard calibration is discussed. Efficiencies of available approaches for decreasing and controlling matrix effects are evaluated and compared. SPME from a soil sample headspace with internal standard calibration was identified as one of the promising approaches to achieve fast, simple, precise, and accurate on-site quantification of a wide range of organic pollutants in soil. Cold-fiber SPME has a significant development potential, because it is capable of providing lowest detection limits together with a minimum matrix effect. Perspectives for future development of the field are outlined

Determination of 1-methyl-1H-1,2,4-triazole in soils contaminated by rocket fuel using solid-phase microextraction, isotope dilution and gas chromatography–mass spectrometry

Environmental monitoring of Central Kazakhstan territories where heavy space booster rockets land requires fast, efficient, and inexpensive analytical methods. The goal of this study was to develop a method for quantitation of the most stable transformation product of rocket fuel, i.e., highly toxic unsymmetrical dimethylhydrazine – 1-methyl-1H-1,2,4-triazole (MTA) in soils using solid-phase microextraction (SPME) in combination with gas chromatography–mass spectrometry. Quantitation of organic compounds in soil samples by SPME is complicated by a matrix effect. Thus, an isotope dilution method was chosen using deuterated analyte (1-(trideuteromethyl)-1H-1,2,4-triazole; MTA-d3) for matrix effect control. The work included study of the matrix effect, optimization of a sample equilibration stage (time and temperature) after spiking MTA-d3 and validation of the developed method. Soils of different type and water content showed an order of magnitude difference in SPME effectiveness of the analyte. Isotope dilution minimized matrix effects. However, proper equilibration of MTA-d3 in soil was required. Complete MTA-d3 equilibration at temperatures below 40 °C was not observed. Increase of temperature to 60 °C and 80 °C enhanced equilibration reaching theoretical MTA/MTA-d3 response ratios after 13 and 3 h, respectively. Recoveries of MTA depended on concentrations of spiked MTA-d3 during method validation. Lowest spiked MTA-d3 concentration (0.24 mg kg−1) provided best MTA recoveries (91–121%). Addition of excess water to soil sample prior to SPME increased equilibration rate, but it also decreased method sensitivity. Method detection limit depended on soil type, water content, and was always below 1 mg kg−1. The newly developed method is fully automated, and requires much lower time, labor and financial resources compared to known methods

Возможности по снижению пределов обнаружения методик определения продуктов трансформации несимметричного диметилгидразина в объектах окружающей среды

Большинство ракет среднего и тяжелого класса, запускаемых с территории Казахстана, России, Китая и других стран по сей день используют в качестве топлива высокотоксичный несимметричный диметилгидразин (НДМГ). Изучение путей миграции, распространения и накопления продуктов трансформации НДМГ в окружающей среде, а также оценка влияния ракетно-космической деятельности на здоровье населения в настоящий момент затруднена ввиду отсутствия методик определения следовых концентраций данных соединений в анализируемых образцах. В данной работе сделан краткий обзор методов и подходов, которые могут быть использованы для разработки подобных методик. Пределы обнаружения на уровне триллионных долей могут быть достигнуты за счет применения наиболее селективных и чувствительных методов на основе газовой и жидкостной хроматографии с детектированием методом тандемной масс-спектрометрии либо масс-спектрометрии высокого разрешения. Также необходима 1000-кратное концентрирование образцов в ходе пробоподготовки либо использование интегрированных подходов, таких как динамический парофазный анализ. Особое внимание при разработке и использовании таких методик необходимо уделять чистоте воздуха в лаборатории, реактивов, посуды и используемого оборудования

Perspectives and challenges of on-site quantification of organic pollutants in soils using solid-phase microextraction

This study explores the current state-of-the-art progress toward on-site quantification of organic pollutants in soils with solid-phase microextraction (SPME). In spite of many available methods, only few publications report on-site analyses of soil samples by SPME. To date, the only application of SPME for the on-site quantification of organic pollutants in soil has been devoted to trichloroethylene. The problem of matrix effects limiting quantification by external standard calibration is discussed. Efficiencies of available approaches for decreasing and controlling matrix effects are evaluated and compared. SPME from a soil sample headspace with internal standard calibration was identified as one of the promising approaches to achieve fast, simple, precise, and accurate on-site quantification of a wide range of organic pollutants in soil. Cold-fiber SPME has a significant development potential, because it is capable of providing lowest detection limits together with a minimum matrix effect. Perspectives for future development of the field are outlined.This is a manuscript of an article published as Kenessov, Bulat, Jacek A. Koziel, Nadezhda V. Bakaikina, and Dina Orazbayeva. "Perspectives and challenges of on-site quantification of organic pollutants in soils using solid-phase microextraction." TrAC Trends in Analytical Chemistry 85 (2016): 111-122. DOI: 10.1016/j.trac.2016.04.007. Posted with permission.</p

Determination of 1-methyl-1H-1,2,4-triazole in soils contaminated by rocket fuel using solid-phase microextraction, isotope dilution and gas chromatography–mass spectrometry

Environmental monitoring of Central Kazakhstan territories where heavy space booster rockets land requires fast, efficient, and inexpensive analytical methods. The goal of this study was to develop a method for quantitation of the most stable transformation product of rocket fuel, i.e., highly toxic unsymmetrical dimethylhydrazine – 1-methyl-1H-1,2,4-triazole (MTA) in soils using solid-phase microextraction (SPME) in combination with gas chromatography–mass spectrometry. Quantitation of organic compounds in soil samples by SPME is complicated by a matrix effect. Thus, an isotope dilution method was chosen using deuterated analyte (1-(trideuteromethyl)-1H-1,2,4-triazole; MTA-d3) for matrix effect control. The work included study of the matrix effect, optimization of a sample equilibration stage (time and temperature) after spiking MTA-d3 and validation of the developed method. Soils of different type and water content showed an order of magnitude difference in SPME effectiveness of the analyte. Isotope dilution minimized matrix effects. However, proper equilibration of MTA-d3 in soil was required. Complete MTA-d3 equilibration at temperatures below 40 °C was not observed. Increase of temperature to 60 °C and 80 °C enhanced equilibration reaching theoretical MTA/MTA-d3 response ratios after 13 and 3 h, respectively. Recoveries of MTA depended on concentrations of spiked MTA-d3 during method validation. Lowest spiked MTA-d3 concentration (0.24 mg kg−1) provided best MTA recoveries (91–121%). Addition of excess water to soil sample prior to SPME increased equilibration rate, but it also decreased method sensitivity. Method detection limit depended on soil type, water content, and was always below 1 mg kg−1. The newly developed method is fully automated, and requires much lower time, labor and financial resources compared to known methods.This is a manuscript of an article published as Yegemova, Saltanat, Nadezhda V. Bakaikina, Bulat Kenessov, Jacek A. Koziel, and Mikhail Nauryzbayev. "Determination of 1-methyl-1H-1, 2, 4-triazole in soils contaminated by rocket fuel using solid-phase microextraction, isotope dilution and gas chromatography–mass spectrometry." Talanta 143 (2015): 226-233. DOI: 10.1016/j.talanta.2015.05.045. Posted with permission.</p

Determination of transformation products of unsymmetrical dimethylhydrazine in water using vacuum-assisted headspace solid-phase microextraction

Summarization: A new, sensitive and simple method based on vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) followed by gas chromatography-mass-spectrometry (GC–MS), is proposed for the quantification of rocket fuel unsymmetrical dimethylhydrazine (UDMH) transformation products in water samples. The target transformation products were: pyrazine, 1-methyl-1H-pyrazole, N-nitrosodimethylamine, N,N-dimethylformamide, 1-methyl-1Н-1,2,4-triazole, 1-methyl-imidazole and 1H-pyrazole. For these analytes and within shorter sampling times, Vac-HSSPME yielded detection limits (0.5–100 ng L−1) 3–10 times lower than those reported for regular HSSPME. Vac-HSSPME sampling for 30 min at 50 °C yielded the best combination of analyte responses and their standard deviations (24 h). Finally, multiple Vac-HSSME proved to be an efficient tool for controlling the matrix effect and quantifying UDMH transformation products.Παρουσιάστηκε στο: Journal of Chromatography