The simple, quick and effective methods for the analysis of epichlorohydrin (ECH) in water and sewage samples with the use of gas chromatography have been presented. From among all the methods developed, the procedures for monitoring drinking-water quality and the methods which allow the determination of epichlorohydrin in sewage samples have been selected.
The limits of ECH detection have been determined by direct aqueous injection (DAI) into the chromatographic column and an analysis with the application of a flame ionization detector (FID), a mass spectrometry detector (MS), an electron capture detector (ECD) and atomic emission detection (AED) detectors. The method allows the determination of ECH in water samples at the concentration level of 0.1 mg l−1. Moreover, the developed methods of water samples preparation for chromatographic analysis using the following extraction methods: headspace (HS), stripping with adsorption on solid phase, liquid–liquid extraction (LLE), solid phase extraction (SPE) and solid phase microextraction (SPME) have been evaluated. The limits of ECH detection for each procedure with the application of gas chromatography (GC) combined with various detectors have been determined and their statistical evaluation has been presented. The SPME method allowed us to determine ECH in water samples at the concentration levels of 1.0 ng l−1.
The results of studies on the choice of the selective methods allowing ECH analysis in sewage samples have been demonstrated. The applied SPME method was found to be a quick and effective technique to determine micro trace amounts of ECH in samples containing high amounts of various organic compounds. 相似文献
ABSTRACT: BACKGROUND: Recently there has been a rapid increase in approaches to assess the effects of cigarette smoke in vitro. Despite a range of gravimetric and chemical methods, there is a requirement to identify simpler and more reliable methods to quantify in vitro whole smoke dose, to support extrapolation and comparisons to human/in vivo dose. We have previously characterised an in vitro exposure system using a Borgwaldt RM20S smoking machine and a chamber exposing cellular cultures to whole smoke at the air-liquid interface. In this study we demonstrate the utility of a quartz crystal microbalance (QCM), using this exposure system, to assess real-time cigarette smoke particulate deposition during a 30 minute smoke exposure. Smoke was generated at various dilutions (1:5--1:400, smoke:air) using two cigarette products, 3R4F Kentucky reference and 1 mg commercially available cigarettes. The QCM, integrated into the chamber, assessed particulate deposition and data generated was compared to traditional chemical spectrofluorometric analysis. RESULTS: The QCM chamber was able to detect mass differences between the different products within the nanogram range. 3R4F reference cigarette smoke deposition ranged from 25.75 [PLUS-MINUS SIGN]2.30 mug/cm2 (1:5) to 0.22 [PLUS-MINUS SIGN]0.03 mug/cm2 (1:400). 1 mg cigarette smoke deposition was less and ranged from 1.42 [PLUS-MINUS SIGN]0.26 mug/cm2 (1:5), to 0.13 [PLUS-MINUS SIGN]0.02 mug/cm2 (1:100). Spectrofluorometric analysis demonstrated statistically significant correlation of particulate deposition with the QCM (p < 0.05), and regression R2 value were 97.4 %. The fitted equation for the linear model which describes the relationship is: QCM = [MINUS SIGN]0.6796 + 0.9744 chemical spectrofluorescence CONCLUSIONS: We suggest the QCM is a reliable, effective and simple tool that can be used to quantify smoke particulate deposition in real-time, in vitro and can be used to quantify other aerosols delivered to our chamber for assessment. 相似文献
Pressurized liquid extraction (PLE) is a fully automated extraction technique for isolation of analytes from solid samples. This technique combines elevated temperature and pressure of liquid solvents during the extraction process. In this study the efficiency of a PLE system for the isolation of wide range of analytes (polychlorinated biphenyls and organic pesticides from sediments under different pressure and temperature conditions) was investigated. The temperature 100 degrees C and pressure 6.9 MPa (1000 p.s.i.; 1 p.s.i.=6894.76 Pa) were found to be the most efficient from all investigated conditions. Using these PLE parameters, the average recoveries for most of the analytes were in the range 80-105% and relative standard deviation was usually under 15%. The conditions of determination of analytes in the extracts using GC-MS were established. Some problems occurring during the analysis of real samples, such as coelution of analytes, were established. The influence of internal standard addition on the final analysis results was determined. 相似文献
Activity concentrations and inventory for 238Pu, 239+240Pu, 241Am, 90Sr, and 137Cs in soil from Tatra Mountains of Poland are presented. Soil samples were collected using 10 cm diameter cores down to 10
cm and sliced into 3 slices. Details of the applied procedure are described with the quality assurance program. The maximum
activity concentrations found for various samples were: 1782±13 Bq/kg, 17.4±0.9 Bq/kg, 3.4±0.3 Bq/kg and 84±7 Bq/kg for 137Cs, 239+240Pu, 241Am and 90Sr, respectively. The maximum cumulated deposition of 239+240Pu is 201±8 Bq/m2. The origin of radionuclides is discussed, based mostly on the observed isotopic ratio of Pu. Significant correlations were
found between 239+240Pu, 241Am and 137Cs. The effective vertical migration rate seems to be in the order of: 90Sr≫Pu>Am>Cs. 相似文献
A new method for determination of fluoride in toothpaste employing the headspace solid-phase microextraction (HS-SPME) followed by gas chromatography/flame ionization detection (GC/FID) has been proposed. It is a development of the method for determination of fluoride using trimethylchlorosilane (TMCS) as the derivatization reagent to form trimethylfluorosilane (TMFS), with the liquid/liquid extraction (LLE) step replaced by HS-SPME. To introduce the latter, it was necessary to determine the conditions of the reaction and to optimize the two stages of the SPME procedure: extraction and desorption. The parameters of the SPME analysis using carboxen/polydimethylsiloxane (CAR/PDMS) fiber were defined and compared with the corresponding ones for the LLE method, used as a reference. Also, these two methods were compared with respect to their linearity, precision, and accuracy. Results from toothpaste analyses using these two methods were highly correlated, indicating the potential to use the SPME extraction as an inexpensive and solventfree alternative to the LLE method. 相似文献
The non-doped AlAs/GaAs distributed Bragg reflectors (DBRs) with density of misfit dislocation (MD) close to zero had been obtained. The reduction of MD density was achieved by increasing temperature distribution homogeneity on the growing crystal in consequence of higher rotation rate of the wafer. Two structures of DBR were crystallized using molecular beam epitaxy (MBE) under the same optimal growth condition. The growth runs differ only in the rotation rate of the wafers. X-ray topograph showed no residual MDs in case of faster rotation. The DBR structure with residual MD density is still highly strained. No additional relaxation process has occurred, what was confirmed by an angular position of DBR zeroth-order peak on high-resolution X-ray diffractometry (HRXRD) rocking curve. 相似文献
A new sample clean-up procedure based on solid-phase extraction (SPE) sorbents was proposed for the determination of pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in soils and sediments. The main purpose of the research was to find a combination of sorbents for the SPE method that would permit the determination of many types of analytes (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, N-, P- and Cl-containing pesticides) in a single run. Elution profiles for both the analytes and the interfering components were determined for several types of SPE sorbents (alumina, silica and surface-modified silica) and combinations of them. The efficiency of the clean-up method developed was evaluated using real soil samples. 相似文献