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- Author or Editor: Z.H. Zhang x
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Abstract
To effectively extract organohalogens from human hair, two factors, the extracting time and hair length on the extraction efficiency of organohalogens were studied by neutron activation analysis (NAA) and gas chromatograph-electron capture detector (GC-ECD), respectively. Furthermore, the concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in hair samples from angioma and control babies were also measured by the established method. The results indicated that the optimal Soxhlet-extraction time for EOX and EPOX in hair was from 8 to 11 hours, and the extraction efficiencies for organochlorine pesticides in hair were in the order of powder >2 mm>5 mm. Also, the mean levels of EOC1 and EPOC1 in hair of the angioma babies were significantly higher than those in the control babies (P EOC1<0.01; P EPOC1<0.05), which implied the possible relationship between the environmental pollution and angioma.
Abstract
Five column experiments have been carried out to investigate the effect of flow rate on the breakthrough curves (BTCs) of phosphate, fulvic acid, and uranium(VI) onto a silica column. Both BTCs of phosphate and fulvic acid, and three BTCs of uranium(VI) in the presence and absence of phosphate or fulvic acid at high flow rate published in the previous paper [<cite>1</cite>] were compared with corresponding initial parts of BTCs at low flow rate in this paper. Each BTC in this paper was expressed as both C/Co–t and C/Co–V/Vo plots, where C and Co are the concentrations in the influent and the effluent respectively, t and V are the time and the effluent volume from the start of injection of pulse solution respectively, Vo is the pore volume of the SiO2 column. Based on the experimental results and the relationship among V, t, and flow rate F, it was found that there are advantages to using C/Co–V/Vo plot as BTC to study the effect of flow rate. Based on these comparisons of C/Co–V/Vo plots at different flow rates and the theoretical analysis from the Bohart–Adams sorption model, it was found that the right shift (increase in V/Vo of breakthrough), the left shift (decrease in V/Vo of breakthrough), and the non-shift (non-change in V/Vo of breakthrough) of initial parts of BTCs with increasing flow rate are certain to occur instead of only left shift and that three different trends of shifts can be mainly attributed to different rate-controlling mechanisms of sorption process.
Abstract
The concentrations of extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX) in placenta, umbilical cord and hair of mothers delivering disabled or normal newborns as well as the compositions of EPOCl in three analyzed matrices were determined by a combination of NAA, gas chromatography and chemical separation. The results indicated that both EOX and EPOX decreased in the order: hair > umbilical cord > placenta. Organochlorines were the major fraction of organohalogens. More than 77% of EPOCl were unidentified. High organohalogens exposure may induce adverse health effects, and hair, as a biomonitor for organohalogens assessment, is more recommendable.
Abstract
Cyclic neutron activation analysis method was conducted for determination of Se in food samples. High accuracy and good precision were proved by analyzing certified reference materials (CRMs) of chicken (GBW10018), rice (GBW10010) and cabbage (GBW10014). The detection limits for the three CRMs reached 0.16, 0.66 and 1.2 ng after 6 cycles at the 161.9 keV γ-peak from 77mSe, under a neutron flux of 9.0 × 1011 n cm−2 s−1 and the conditions of 30 s irradiation, 2 s decay, 30 s counting and 2 s waiting, significantly lower than those of conventional neutron activation analysis without any cycles, which were 0.94, 3.6 and 4.3 ng, respectively.
Abstract
A fully automated adiabatic calorimeter controlled on line by a computer used for heat capacity measurements in the temperature range from 80 to 400 K was constructed. The hardware of the calorimetric system consisted of a Data Acquisition/Switch Unit, 34970A Agilent, a 7 1/2 Digit Nano Volt /Micro Ohm Meter, 34420A Agilent, and a P4 computer. The software was developed according to modern controlling theory. The adiabatic calorimeter consisted mainly of a sample cell equipped with a miniature platinum resistance thermometer and an electric heater, two (inner and outer) adiabatic shields, two sets of six junction differential thermocouple piles and a high vacuum can. A Lake Shore 340 Temperature Controller and the two sets of differential thermocouples were used to control the adiabatic conditions between the cell and its surroundings. The reliability of the calorimeter was verified by measuring the heat capacities of synthetic sapphire (α-Al2O3), Standard Reference Material 720. The deviation of the data obtained by this calorimeter from those published by NIST was within ±0.1% in the temperature range from 80 to 400 K.
A detail study of distribution, host range, and seasonal pattern of western flower thrips (WFT), Frankliniella occidentalis (Pergande), in Yunnan Province was conducted in 2004–2006. The pest is distributed throughout the province and was found in 22 out of 25 widely spaced locations surveyed. WFT was found feeding on 45 species of vegetables, ornamentals, and weeds in the province. Seasonal pattern of WFT on vegetables planted in open field and inside greenhouses was similar and, with exception of minor local differences, did not differ from information generated elsewhere. These findings may provide some useful data for the management of this and possibly other thrips pests in Yunnan.
Abstract
The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants.
Abstract
The concentrations and distributions of total halogen (TX), extractable organohalogen (EOX) and extractable persistent organohalogen (EPOX) were determined in 20 kinds of yogurt specimens collected from Chinese supermarkets using neutron activation analysis (NAA) and gas chromatography equipped with a 63Ni electron capture detector (GC-ECD). The results indicated that the halogens in yogurt mainly existed as non-extractable organohalogen compounds. About 25–30% of EOX was EPOX. EOCl and EPOCl were the main organohalogen species in yogurt. The average concentration of the identified organochlorine, such as organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), was below 4% of EPOCl.
Summary
As a new form of traditional Chinese medicine (TCM), Zuojin pill extract is made containing Coptidis rhizoma (the rhizome of Coptis chinesis Franch. [Ranunculaceae]) and Euodiae fructus (the unripe fruit of Euodia rutaecarpa [Juss.] Benth. [Rutaceae]) at the ratio of 6:1 (w/w) and has been most widely used in TCM to treat gastro-intestinal disorders. However, the quality control is insufficient. For establishing an analysis method for the effective quality control of Zuojin pill extract, the active components of three protoberberine alkaloids (coptisine, palmatine, berberine, components from C. rhizoma) and two indolequinoline alkaloids (evodiamine, rutaecarpine, components from E. fructus) in Zuojin pill extract were determined simultaneously by high-performance liquid chromatography. Chromatographic separations were performed on an Inertsil ODS-3 column (4.6 mm × 250 mm, 5 μm). Elution was carried out at 25°C under isocratic conditions by using 25 mmol L−1 KH2PO4-25 mmol L−1 SDS-acetonitrile (1:1:2, v/v/v, adjusted pH to 3.0 using phosphoric acid) as a mobile phase with a flow rate of 0.5 mL min−1. Detection wavelength was set at 264 nm. Good linearity was obtained with correlation coefficient higher than 0.999 for all the analytes over the investigated concentration ranges. Three batches of Zuojin pill extract were successfully analyzed. The average percentages of coptisine, palmatine, berberine, evodiamine, and rutaecarpine in Zuojin pill extract were 5.35%, 3.92%, 16.64%, 0.03%, and 0.03%, respectively. Consequently, these protoberberine and indolequinoline alkaloids could be identified and determined easily by the established high-performance liquid chromatography (HPLC) method which can be used to evaluate and control the quality of Zuojin pill extract.
