Quantification of trace transformation products of rocket fuel unsymmetrical dimethylhydrazine in sand using vacuum-assisted headspace solid-phase microextraction.

Quantification of unsymmetrical dimethylhydrazine transformation products in solid samples is an important stage in monitoring of environmental pollution caused by heavy rockets launches. The new method for simultaneous quantification of unsymmetrical dimethylhydrazine transformation products in sand samples using vacuum-assisted headspace solid-phase microextraction without addition of water followed by gas chromatography-mass spectrometry is proposed. Decreasing air evacuation time from 120 to 20 s at 23 °C resulted in increased responses of analytes by 25-46% and allowed obtaining similar responses as after evacuation at -30 °C. The best combination of responses of analytes and their relative standard deviations (RSDs) was achieved after air evacuation of a sample (m = 1.00 g) for 20 s at 23 °C, incubation for 30 min at 40 °C, and 30-min extraction at 40 °C by Carboxen/polydimethylsiloxane (Car/PDMS) fiber. The method was validated in terms of linearity (R2=0.9912-0.9938), limits of detection (0.035 to 3.6 ng g-1), limits of quantification (0.12-12 ng g-1), recovery (84-97% with RSDs 1-11%), repeatability (RSDs 3-9%), and reproducibility (RSDs 7-11%). It has a number of major advantages over existing methods based on headspace solid-phase microextraction-lower detection limits, better accuracy and precision at similar or lower cost of sample preparation. The developed method was successfully applied for studying losses of analytes from open vials with model sand spiked with unsymmetrical dimethylhydrazine transformation products. It can be recommended for analysis of trace concentrations of unsymmetrical dimethylhydrazine transformation products when studying their transformation, migration and distribution in contaminated sand.

Modeling the effect of temperature on solid-phase microextraction of volatile organic compounds from air by polydimethylsiloxane coating using finite element analysis.

A development of analytical methods based on solid-phase microextraction (SPME) is a very time- and labor-consuming task. The finite element methods have found a wide application in SPME modeling for faster and more accurate optimization of analytical methods. In this work, a computational model for predicting the effect of temperature on extraction of VOCs from air onto SPME coating based on polydimethylsiloxane (PDMS) has been developed using COMSOL Multiphysics® (CMP) software. Most suitable methods and models for estimating the diffusion coefficients of analytes in air and coating, and coating-air distribution constants of the analytes at different extraction temperatures were chosen. The Fuller method was chosen for calculating diffusion coefficients of analytes in air due to its simplicity and reliability. Coating-air distribution constants at different temperatures were estimated using van't Hoff equation. A combination of inverse gas chromatography on a capillary column with a similar stationary phase for estimating diffusion coefficients and linear temperature programmed retention indices (LTPRI) for estimating coating-air distribution constants at initial temperature were chosen for modeling purposes because in most cases it provided lowest values of root-mean-square difference from experimental extraction profiles from 125 mL bulb at 25 and 40 °C. The developed model can be recommended for faster and simpler optimization of the methods of air sampling using PDMS SPME fiber. It can also be used for obtaining extraction profiles at fluctuating temperatures.

Quantification of transformation products of rocket fuel unsymmetrical dimethylhydrazine in air using solid-phase microextraction.

Quantification of unsymmetrical dimethylhydrazine transformation products in ambient air is important for assessing the environmental impact of heavy rocket launches. There are very little data of such analyses, which is mainly caused by the low number of analytes covered by the available analytical methods and their complexity. A simple and cost-efficient method for accurate simultaneous determination of seven unsymmetrical dimethylhydrazine transformation products in air using solid-phase microextraction followed by gas chromatography-mass spectrometry was developed. The method was optimized for air sampling and solid-phase microextraction from 20-mL vials, which allows full automation of analysis. The extraction for 5 min by Carboxen/polydimethylsiloxane fiber from amber vials and desorption for 3 min provided the greatest analytes' responses, lowest relative standard deviations, linear calibration (R2 ≥ 0.99), and limits of detection from 0.12 to 0.5 µg/m3 . Samples with concentrations 500 µg/m3 can be stored at 21 ± 1°C without substantial losses (1-11%) for up to 24 h, while air samples with concentrations 10 and 50 µg/m3 stored for up to 24 h can be used for accurate quantification of only two and four out of seven analytes, respectively. The developed method was successfully tested for the analysis of air above real soil samples contaminated with unsymmetrical dimethylhydrazine rocket fuel.

Trends and health impacts of major urban air pollutants in Kazakhstan.

The air quality in cities in Kazakhstan has been poorly investigated despite the worsening conditions. This study evaluates national air pollution monitoring network data (Total Suspended Particle-TSP, NO2, SO2, and O3) from Kazakhstan cities and provides estimates of excess mortality rates associated with PM2.5 exposure using the Global Exposure Mortality Model (GEMM) concentration-response function. Morbidity rates associated with PM10 exposure were also estimated. Annual average (2015-2017) population-weighted concentrations were Kazakhstan cities was 157, 51, 29, and 41 µg m-3 for TSP, NO2, SO2, and O3 respectively. We estimated a total of 8134 adult deaths per year attributable to PM2.5 (average over 2015-2017) in the selected 21 cities of Kazakhstan. The leading causes of death were ischemic heart disease (4080), stroke (1613), lower respiratory infections (662), chronic obstructive pulmonary disease (434), lung cancer (332). The per capita mortality rate attributable to ambient air pollution (per 105 adults per year) was less than 150 in nine cities, between 150 and 204 in nine cities, and between 276 and 373 in three industrial cities (Zhezkazgan, Temirtau, and Balkhash). Implications: Quantitative information on the health impacts of air pollution can be useful for decision-makers in Kazakhstan to justify environmental policies and identify policy and funding priorities for addressing air pollution issues. This information can also be useful for policymakers by improving the quality of government-funded environmental reports and strategic documents, as they have many shortcomings in terms of the selection of air quality indicators, identification of priority pollutants, and identification of sources of pollution. This study has high significance due to the lack of data and knowledge in Central Asia, especially Kazakhstan.

Assessing air quality changes in large cities during COVID-19 lockdowns: The impacts of traffic-free urban conditions in Almaty, Kazakhstan.

Number of cities worlwide experienced air quality improvements during COVID-19 lockdowns; however, such changes may have been different in places with major contributions from nontraffic related sources. In Almaty, a city-scale quarantine came into force on March 19, 2020, which was a week after the first COVID-19 case was registered in Kazakhstan. This study aims to analyze the effect of the lockdown from March 19 to April 14, 2020 (27 days), on the concentrations of air pollutants in Almaty. Daily concentrations of PM2.5, NO2, SO2, CO, O3, and BTEX were compared between the periods before and during the lockdown. During the lockdown, the PM2.5 concentration was reduced by 21% with spatial variations of 6-34% compared to the average on the same days in 2018-2019, and still, it exceeded WHO daily limit values for 18 days. There were also substantial reductions in CO and NO2 concentrations by 49% and 35%, respectively, but an increase in O3 levels by 15% compared to the prior 17 days before the lockdown. The concentrations of benzene and toluene were 2-3 times higher than those during in the same seasons of 2015-2019. The temporal reductions may not be directly attributed to the lockdown due to favorable meteorological variations during the period, but the spatial effects of the quarantine on the pollution levels are evidenced. The results demonstrate the impact of traffic on the complex nature of air pollution in Almaty, which is substantially contributed by various nontraffic related sources, mainly coal-fired combined heat and power plants and household heating systems, as well as possible small irregular sources such as garbage burning and bathhouses.

Trends and health impacts of major urban air pollutants in Kazakhstan.

Air quality in Kazakhstan cities has been poorly investigated despite their deteriorating situations. This study evaluates the national air pollution monitoring network data (PM10, NO2, SO2, and O3) in Kazakhstan cities, and provides the estimates of excess mortality rates associated with PM2.5 exposure using the Global Exposure Mortality Model (GEMM) concentration-response function. Morbidity rates associated with PM10 exposure were also estimated. Firstly, an air quality-based priority ranking of the cities was suggested based on the annual concentrations of the pollutants during the period of 3 years between 2015 and 2017. Nur-Sultan, Almaty, Ust-Kamenogorsk, and Aktobe were identified as the most polluted cities by PM10, NO2, SO2, and O3 respectively. Then, the exposure-response assessment was conducted for 21 cities. In major cities of Kazakhstan attributable to ambient air pollution per capita, mortality rate is 1 193 per 100 000 population per year, which is 8.97 times higher than in Europe. It is estimated that fine particulate matter exposure in the major cities of Kazakhstan causes 101 139 premature deaths annually. This study provides quantitative information on potential public health risks and impacts of air pollution, which is valuable for decision-makers to justify national environmental policies. Implications: Quantitative information on health impacts from air pollution can be useful for decision makers in Kazakhstan to justify environmental policies and identify policy and funding priorities for tackling air pollution issues. It can be also useful for policy makers in improving the quality of government funded environmental reports and strategic documents as they have many shortcomings in terms of selection of air quality indicators, identification of priority pollutants, identification of sources of pollution. This study has high significance due to the lack of data and knowledge in the region of Central Asia, in particular, of Kazakhstan.

Modeling solid-phase microextraction of volatile organic compounds by porous coatings using finite element analysis.

Experimental optimization of analytical methods based on solid-phase microextraction (SPME) is a complex and labor-intensive process associated with uncertainties. Using the theoretical basics of SPME and finite element analysis software for the optimization proved to be an efficient alternative. In this study, an improved finite element analysis-based model for SPME of volatile organic compounds (VOCs) by porous coatings was developed mainly focussing on the mass transport in coatings. Benzene and the Carboxen/polydimethylsiloxane (Car/PDMS) coating were used as the model VOC and a porous SPME coating, respectively. It has been established that in the coating, volumetric fractions of Carboxen, PDMS, and air are 33, 42 and 24%, respectively. Knudsen diffusion in micropores can slow down a mass transport of analytes in the coating. When PDMS was considered as the solid part of the coating, lower root-mean-square deviation of the modeling results from experimental data was observed. It has been shown that the developed model can be used to model the extraction of VOCs from air and water samples encountered in a typical SPME development method procedure. It was possible to determine system equilibration times and use them to optimize sample volume and Henry's law constant. The developed model is relatively simple, fast, and can be recommended for optimization of extraction parameters for other analytes and SPME coatings. The diffusivity of analytes in a coating is an important property needed for improved characterization of existing and new SPME polymers and analytical method optimization.

Effects of oxidant and catalyst on the transformation products of rocket fuel 1,1-dimethylhydrazine in water and soil.

Existing methods for cleanup of wastewaters and soils polluted with the extremely toxic rocket fuel unsymmetrical dimethylhydrazine (UDMH) are mainly based on the treatment with various oxidative reagents. Until now, the assessment of their effectiveness was based on the residual content of UDMH and did not take into account the possibility of the formation of a large number of potentially dangerous nitrogen-containing transformation products (TPs). In this study, using the recently developed approach based on high-resolution Orbitrap mass spectrometry, the comprehensive characterization of UDMH TPs formed by the action of air oxygen and different oxidants (Fenton's reagent, KMnO4, HOCl, H2O2 in the presence of Cu2+ and [Fe (EDTA)]- catalysts) typically used to detoxify spill sites was performed. The range of the identified molecular formulas of TPs comprised 303 compounds of various classes. Among them, there is a number of major products not previously described in the literature. It was established that none of the investigated oxidative reagents ensures complete conversion of rocket fuel to safe compounds. The hydrogen peroxide based reagents, particularly H2O2 + Na [Fe (EDTA)] system currently used in Kazakhstan, give the greatest number of TPs, for many of which a toxicity was not characterized so far. The majority of the compounds found in model solutions was detected in extracts of soil from the crash site of the Proton carrier rocket, which was subjected to the on-site reagent treatment. During successive treatments, along with the decrease in the number of detectable UDMH TPs, their ratios change in favor of amines.

Comparative assessment of using Miscanthus × giganteus for remediation of soils contaminated by heavy metals: a case of military and mining sites.

Contamination of soil by heavy metals is among the important environmental problems due to their toxicity and negative impact to human health and the environment. An effective method for cleaning the soil from heavy metals is phytoremediation using the second-generation bioenergy species Miscanthus × giganteus. The purpose of this research is to study the benefits of M. × giganteus cultivation at the soils taken from the mining and former military sites contaminated by As, Pb, Zn, Co, Ni, Cr, Cu, V, Mn, Sr, and U as well as at the soil artificially contaminated by Zn and Pb, to evaluate the physiological parameters of the plant, to establish peculiarities of the phytoremediation process, and to characterize the behavior of the plant in relation to the nature and concentrations of the metals in the soils. Results showed that M. × giganteus was resistant to heavy metals (tolerance index ≥ 1) and that the greatest portion of metals accumulated in the root system. The morphological parameters of the plant while grown on different soils are influenced by soil type and the content of contaminants. The stress effect while growing M. × giganteus on soil artificially contaminated by Zn and Pb was evaluated by measuring the content of pigments (chlorophylls a, b, and carotenoids) in the plant's leaves. The decrease in the total content of chlorophylls, Сa + b/Сcar and transpiration rate of water along with the increase in the water absorbing capacity were observed. The accumulation of heavy metals in different parts of the plant was determined; bioaccumulation coefficient and values of translocation factor were calculated. The obtained results showed that M. × giganteus was an excluder plant for nine highly toxic elements (As, Pb, Zn, Co, Ni, Cr, Cu, V, U) and an accumulator species for the moderately dangerous elements (Mn, Sr). Further research will be focused on the extraction of stable stimulated plant-growth-promoting rhizobacteria from the rhizosphere of M. × giganteus and formulation on that base the plant-bacterial associations as well as on the comparison of the plant physiological parameters, biochemical soil activity, and accumulation of heavy metals in the Miscanthus tissues between first and second vegetations.

Development of Time-Weighted Average Sampling of Odorous Volatile Organic Compounds in Air with Solid-Phase Microextraction Fiber Housed inside a GC Glass Liner: Proof of Concept.

Finding farm-proven, robust sampling technologies for measurement of odorous volatile organic compounds (VOCs) and evaluating the mitigation of nuisance emissions continues to be a challenge. The objective of this research was to develop a new method for quantification of odorous VOCs in air using time-weighted average (TWA) sampling. The main goal was to transform a fragile lab-based technology (i.e., solid-phase microextraction, SPME) into a rugged sampler that can be deployed for longer periods in remote locations. The developed method addresses the need to improve conventional TWA SPME that suffers from the influence of the metallic SPME needle on the sampling process. We eliminated exposure to metallic parts and replaced them with a glass tube to facilitate diffusion from odorous air onto an exposed SPME fiber. A standard gas chromatography (GC) liner recommended for SPME injections was adopted for this purpose. Acetic acid, a common odorous VOC, was selected as a model compound to prove the concept. GC with mass spectrometry (GC⁻MS) was used for air analysis. An SPME fiber exposed inside a glass liner followed the Fick's law of diffusion model. There was a linear relationship between extraction time and mass extracted up to 12 h (R² > 0.99) and the inverse of retraction depth (1/Z) (R² > 0.99). The amount of VOC adsorbed via the TWA SPME using a GC glass liner to protect the SPME was reproducible. The limit of detection (LOD, signal-to-noise ratio (S/N) = 3) and limit of quantification (LOQ, S/N = 5) were 10 and 18 µg·m-3 (4.3 and 7.2 ppbV), respectively. There was no apparent difference relative to glass liner conditioning, offering a practical simplification for use in the field. The new method related well to field conditions when comparing it to the conventional method based on sorbent tubes. This research shows that an SPME fiber exposed inside a glass liner can be a promising, practical, simple approach for field applications to quantify odorous VOCs.

Optimization of Time-Weighted Average Air Sampling by Solid-Phase Microextraction Fibers Using Finite Element Analysis Software.

Determination of time-weighted average (TWA) concentrations of volatile organic compounds (VOCs) in air using solid-phase microextraction (SPME) is advantageous over other sampling techniques, but is often characterized by insufficient accuracies, particularly at longer sampling times. Experimental investigation of this issue and disclosing the origin of the problem is problematic and often not practically feasible due to high uncertainties. This research is aimed at developing the model of the TWA extraction process and optimization of TWA air sampling by SPME using finite element analysis software (COMSOL Multiphysics, Burlington, MA, USA). It was established that sampling by porous SPME coatings with high affinity to analytes is affected by slow diffusion of analytes inside the coating, an increase of their concentrations in the air near the fiber tip due to equilibration, and eventual lower sampling rate. The increase of a fiber retraction depth (Z) resulted in better recoveries. Sampling of studied VOCs using 23 ga Carboxen/polydimethylsiloxane (Car/PDMS) assembly at maximum possible Z (40 mm) was proven to provide more accurate results. Alternative sampling configuration based on 78.5 × 0.75 mm internal diameter SPME liner was proven to provide similar accuracy at improved detection limits. Its modification with the decreased internal diameter from the sampling side should provide even better recoveries. The results obtained can be used to develop a more accurate analytical method for determination of TWA concentrations of VOCs in air using SPME. The developed model can be used to simulate sampling of other environments (process gases, water) by retracted SPME fibers.

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

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 (<15%). 1-Formyl-2,2-dimethylhydrazine and formamide were discarded because of the poor precision and accuracy when using Vac-HSSPME. The recoveries for the rest of the analytes ranged between 80 and 119%. The modified Mininert valve and Thermogreen septum could be used for automated extraction as it ensured stable analyte signals even after long waiting times (>24 h). Finally, multiple Vac-HSSME proved to be an efficient tool for controlling the matrix effect and quantifying UDMH transformation products.

Quantification of transformation products of rocket fuel unsymmetrical dimethylhydrazine in soils using SPME and GC-MS.

Determination of transformation products (TPs) of rocket fuel unsymmetrical dimethylhydrazine (UDMH) in soil is highly important for environmental impact assessment of the launches of heavy space rockets from Kazakhstan, Russia, China and India. The method based on headspace solid-phase microextraction (HS SPME) and gas chromatography-mass spectrometry is advantageous over other known methods due to greater simplicity and cost efficiency. However, accurate quantification of these analytes using HS SPME is limited by the matrix effect. In this research, we proposed using internal standard and standard addition calibrations to achieve proper combination of accuracies of the quantification of key TPs of UDMH and cost efficiency. 1-Trideuteromethyl-1H-1,2,4-triazole (MTA-d3) was used as the internal standard. Internal standard calibration allowed controlling matrix effects during quantification of 1-methyl-1H-1,2,4-triazole (MTA), N,N-dimethylformamide (DMF), and N-nitrosodimethylamine (NDMA) in soils with humus content < 1%. Using SPME at 60 °C for 15 min by 65 µm Carboxen/polydimethylsiloxane fiber, recoveries of MTA, DMF and NDMA for sandy and loamy soil samples were 91-117, 85-123 and 64-132%, respectively. For improving the method accuracy and widening the range of analytes, standard addition and its combination with internal standard calibration were tested and compared on real soil samples. The combined calibration approach provided greatest accuracies for NDMA, DMF, N-methylformamide, formamide, 1H-pyrazole, 3-methyl-1H-pyrazole and 1H-pyrazole. For determination of 1-formyl-2,2-dimethylhydrazine, 3,5-dimethylpyrazole, 2-ethyl-1H-imidazole, 1H-imidazole, 1H-1,2,4-triazole, pyrazines and pyridines, standard addition calibration is more suitable. However, the proposed approach and collected data allow using both approaches simultaneously.

Use of partial order in environmental pollution studies demonstrated by urban BTEX air pollution in 20 major cities worldwide.

Urban air pollution with benzene, toluene, ethyl benzene and xylenes (BTEX) is a common phenomenon in major cities where the pollution mainly originates from traffic as well as from residential heating. An attempt to rank cities according to their BTEX air pollution is not necessarily straight forward as we are faced with several individual pollutants simultaneously. A typical procedure is based on aggregation of data for the single compounds, a process that not only hides important information but is also subject to compensation effects. The present study applies a series of partial ordering tools to circumvent the aggregation. Based on partial ordering, most important indicators are disclosed, and an average ranking of the cities included in the study is derived. Since air pollution measurements are often subject to significant uncertainties, special attention has been given to the possible effect of uncertainty and/or data noise. Finally, the effect of introducing weight regimes is studied. In a concluding section the gross national income per person (GNI) is brought into play, demonstrating a positive correlation between BTEX air pollution and GNI. The results are discussed in terms of the ability/willingness to combat air pollution in the cities studied. The present study focuses on Almaty, the largest city in Kazakhstan and compares the data from Almaty to another 19 major cities around the world. It is found that the benzene for Almaty appears peculiar high. Overall Almaty appears ranked as the 8th most BTEX polluted city among the 20 cities included in the study.

Determination of semi-volatile additives in wines using SPME and GC-MS.

Parameters of headspace solid-phase microextraction, such as fiber coating (85µm CAR/PDMS), extraction time (2min for white and 3min for red wines), temperature (85°C), pre-incubation time (15min) were optimized for identification and quantification of semi-volatile additives (propylene glycol, sorbic and benzoic acids) in wines. To overcome problems in their determination, an evaporation of the wine matrix was performed. Using the optimized method, screening of 25 wine samples was performed, and the presence of propylene glycol, sorbic and benzoic acids was found in 22, 20 and 6 samples, respectively. Analysis of different wines using a standard addition approach showed good linearity in concentration ranges 0-250, 0-125, and 0-250mg/L for propylene glycol, sorbic and benzoic acids, respectively. The proposed method can be recommended for quality control of wine and disclosing adulterated samples.

Distribution and risk assessment of selected organochlorine pesticides in Kyzyl Kairat village from Kazakhstan.

Concentrations of selected organochlorine pesticides (OCPs), i.e., 4,4'-dichlorodiphenyltrichloroethane (p,p'-DDT), its metabolites (p,p'-DDE, p,p'-DDD), and hexachlorocyclohexanes (HCHs), have been determined in 100 soil samples collected from a contaminated site centered around a former storehouse in the Kyzyl Kairat village, Almaty region, Kazakhstan, which constitutes an exemplary case example. The OCPs were observed in all analyzed soil samples, with predominance of α-HCH, p,p'-DDD, p,p'-DDE, and p,p'-DDT. Total concentrations ranged from 1.38 to 11,100 µg kg(-1) with an average value of 1040 µg kg(-1) for DDT and its metabolites and 0.1 to 438 µg kg(-1) with an average value of 24 µg kg(-1) for HCHs. The observed concentrations of the OCPs were found to be in agreement with previous studies and are rationalized in terms of the possible degradation pathways of DDTs and HCHs. Spatial distribution patterns of OCPs are elucidated by contour maps. Observed concentrations of the OCPs were used to evaluate the cancer risk to humans via ingestion, dermal contact, and inhalation of soil particles. The cancer risk mainly occurs from ingestion, whereas dermal exposure contributes to a minor extent to the total cancer risk. The risk associated with inhalation was found to be negligible. The total cancer risk for the studied OCPs were found to be p,p'-DDT ˃ p,p'-DDE ˃ p,p'-DDD ˃ α-HCH ˃ ß-HCH ˃ γ-HCH.

Simple and accurate quantification of BTEX in ambient air by SPME and GC-MS.

Benzene, toluene, ethylbenzene and xylenes (BTEX) comprise one of the most ubiquitous and hazardous groups of ambient air pollutants of concern. Application of standard analytical methods for quantification of BTEX is limited by the complexity of sampling and sample preparation equipment, and budget requirements. Methods based on SPME represent simpler alternative, but still require complex calibration procedures. The objective of this research was to develop a simpler, low-budget, and accurate method for quantification of BTEX in ambient air based on SPME and GC-MS. Standard 20-mL headspace vials were used for field air sampling and calibration. To avoid challenges with obtaining and working with 'zero' air, slope factors of external standard calibration were determined using standard addition and inherently polluted lab air. For polydimethylsiloxane (PDMS) fiber, differences between the slope factors of calibration plots obtained using lab and outdoor air were below 14%. PDMS fiber provided higher precision during calibration while the use of Carboxen/PDMS fiber resulted in lower detection limits for benzene and toluene. To provide sufficient accuracy, the use of 20mL vials requires triplicate sampling and analysis. The method was successfully applied for analysis of 108 ambient air samples from Almaty, Kazakhstan. Average concentrations of benzene, toluene, ethylbenzene and o-xylene were 53, 57, 11 and 14µgm(-3), respectively. The developed method can be modified for further quantification of a wider range of volatile organic compounds in air. In addition, the new method is amenable to automation.

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 3h, 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.

Quantification of benzene, toluene, ethylbenzene and o-xylene in internal combustion engine exhaust with time-weighted average solid phase microextraction and gas chromatography mass spectrometry.

A new and simple method for benzene, toluene, ethylbenzene and o-xylene (BTEX) quantification in vehicle exhaust was developed based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME) fiber coating. The rationale was to develop a method based on existing and proven SPME technology that is feasible for field adaptation in developing countries. Passive sampling with SPME fiber retracted into the needle extracted nearly two orders of magnitude less mass (n) compared with exposed fiber (outside of needle) and sampling was in a time weighted-averaging (TWA) mode. Both the sampling time (t) and fiber retraction depth (Z) were adjusted to quantify a wider range of Cgas. Extraction and quantification is conducted in a non-equilibrium mode. Effects of Cgas, t, Z and T were tested. In addition, contribution of n extracted by metallic surfaces of needle assembly without SPME coating was studied. Effects of sample storage time on n loss was studied. Retracted TWA-SPME extractions followed the theoretical model. Extracted n of BTEX was proportional to Cgas, t, Dg, T and inversely proportional to Z. Method detection limits were 1.8, 2.7, 2.1 and 5.2 mg m(-3) (0.51, 0.83, 0.66 and 1.62 ppm) for BTEX, respectively. The contribution of extraction onto metallic surfaces was reproducible and influenced by Cgas and t and less so by T and by the Z. The new method was applied to measure BTEX in the exhaust gas of a Ford Crown Victoria 1995 and compared with a whole gas and direct injection method.

Transformation products of 1,1-dimethylhydrazine and their distribution in soils of fall places of rocket carriers in Central Kazakhstan.

In our research, three fall places of first stages of Proton rockets have been studied for the presence and distribution of transformation products of 1,1-dimethylhydrazine (1,1-DMH). Results of identification of transformation products of 1,1-DMH in real soil samples polluted due to rocket fuel spills allowed to detect 18 earlier unknown metabolites of 1,1-DMH being formed only under field conditions. According to the results of quantitative analyses, maximum concentrations of 1-methyl-1H-1,2,4-triazole made up 57.3, 44.9 and 13.3 mg kg(-1), of 1-ethyl-1H-1,2,4-triazole - 5.45, 3.66 and 0.66 mg kg(-1), of 1,3-dimethyl-1H-1,2,4-triazole - 24.0, 17.8 and 4.9 mg kg(-1) in fall places 1, 2 and 3, respectively. 4-Methyl-4H-1,2,4-triazole was detected only in fall places 2 and 3 where its maximum concentrations made up 4.2 and 0.66 mg kg(-1), respectively. The pollution of soils with transformation products of 1,1-DMH was only detected in epicenters of fall places having a diameter of 8 to10 m where rocket boosters landed. The results of a detailed study of distribution of 1,1-DMH transformation products along the soil profile indicate that transformation products can migrate down to the depth of 120 cm, The highest concentrations of 1,1-DMH transformation products were detected, as a rule, at the depth 20 to 60 cm. However, this index can vary depending on the compound, humidity and physical properties of soil, landscape features and other conditions. In the surface layer, as a rule, only semi-volatile products of transformation were detected which was caused by fast evaporation and biodegradation of volatile metabolites.