Interlaboratory comparison of the determination of chlorinated dibenzo-p-dioxins and dibenzofurans according to regulatory methods EN 1948 and EPA 1613b

Four laboratories participated in a collaborative study to determine differences in analytical results generated according to two different compliance methods, US EPA Method 1613b and European Union Method EN 1948 for the determination of chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/CDFs). Various sample matrices containing the analytes at levels ranging from parts-per-quadrillion (ppq) to parts-per-billion (ppb) were used to illustrate differences and similarities between the two analytical methods. The choice of the sample matrices analyzed in this study was made to mirror many of the real-world samples that are of interest to Dow and also to test the laboratories on many different, complex matrices. For this reason, commercially available performance evaluation samples were not used. The study results indicate that the 1613b requirement for confirmation of analyte identity and concentration on a second, polar gas chromatographic column for 2378-tetrachlorodibenzofuran (TCDF) only may lead to quantitative results which are biased high compared to EN 1948 which additionally requires confirmation for all 2378-substituted tetra--through hexachlorodibenzo-p-dioxins and dibenzofurans.

Relationship between dynamic change of copper and dioxin generation in various fly ash

Only limited information on the chemical forms of copper in municipal solid waste incinerator (MSWI) fly ash is available in the literature. Therefore, we performed in situ X-ray absorption near-edge spectroscopy (XANES) experiments involving two types of real fly ash to confirm the behavior of copper in fly ash at secondary formation temperatures for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). CuCl(2).3Cu(OH)(2) was detected in both fly ash types before heating experiments. Cupric compounds in real fly ash were reduced to cuprous compounds or elemental copper at approximately 200 degrees C. The changes in the Cu XANES spectra observed for the two fly ash samples were similar to those observed previously. We also examined the behavior of copper in model fly ash using SiO(2) to investigate the effect of supporting materials and copper content in fly ash on the dynamic changes of copper and amount of dioxins generated. There was little difference between the use of boron nitride (BN) and SiO(2) as a supporting material. The formation mechanisms of PCDDs and PCDFs in both of the model fly ash types were basically the same. Thus, we conclude that the dynamic change of copper in MSWI fly ash during heating is a commonly observed feature, and no simple relationship between the composition of fly ash and the amount of PCDD/PCDF generated or dynamic change of copper is apparent. The dynamic change of copper explained the generated amount and homologue distribution of PCDDs and PCDFs.

Chlorination and thermal degradation of 2-chlorodibenzodioxin and dibenzofuran by CuCl2 or CuCl at 350 degrees C

Chlorination and thermal degradation of 2-chlorodibenzodioxin and dibenzofuran were investigated using sealed tubes at 350 degrees C in the presence of CuCl(2) or CuCl. Twelve organic species, including polychlorobenzenes, were identified and quantified as a function of residence time. Time behaviours of PCDDs and PCDFs regarding destruction processes were compared. The formation of polychlorobenzenes from the thermal heterogeneous degradation of PCDDs was only a minor pathway but it could contribute to the good linear correlation observed between the concentration of polychlorobenzenes and those of PCDD/Fs in the emissions of municipal solid waste incinerators.

Potential source and emission analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China

The Chinese Government ratified the Stockholm Convention on Persistent Organic Pollutants (POPs) on 25 June 2004. As a party to the Convention, China is preparing its National Implementation Plan (NIP), which must be finished and submitted to the Conference of the Parties before November 11, 2006. The emission inventory and strategy for reducing unintentionally formed products is a very complex and difficult part of the NIP. In this paper, we analyzed the potential sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China and calculated their possible emissions. We included municipal solid waste incineration, hazardous and medical waste incineration, pulp bleaching, sodium pentachlorophenate production and usage, illegal electrical and electronic waste ("e-waste") recycling, and ferrous and non-ferrous metal production, and prepared a preliminary analysis of dioxin emissions in China. The results show that ferrous metal production (104.2-6648.3g TEQ), non-ferrous metal production (2.6-3389.8 g TEQ), and sodium pentachlorophenate production and usage (120-368.0 g TEQ) should be major potential sources of dioxins and furans. Moreover, municipal solid waste and hazardous and medical waste incineration (35.5 g TEQ) should also be considered high priority sources owing to a rapidly increasing incineration ratio anticipated for the near future.

Temporal trends and spatial distribution of dioxins and furans in lake trout or lake whitefish from the Canadian Great Lakes

Concentrations of the seventeen 2,3,7,8-substituted, most toxic congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in lake trout (Salvelinus namaycush) or lake whitefish (Coregonus clupeaformis) collected between 1989 and 2003 from the Canadian Great Lakes as a part of the on-going Sport Fish Contaminant Monitoring Program of the Ontario Ministry of the Environment. These monitoring data were used to assess temporal trends and spatial variations of these compounds in the Canadian Great Lakes. Toxic equivalents (TEQs) were calculated using the measured congener concentrations and toxicity equivalency factors (TEFs) published by the World Health Organization in 1998. Five congeners, namely 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PeCDD, 1,2,3,7,8-PeCDF, and 2,3,4,7,8-PeCDF, were the most dominant congeners among the 17 congeners analyzed. The highest TEQs were found for Lake Ontario lake trout (22-54 pg g(-1)) while the TEQs for the other Canadian Great Lakes were 60-95% lower. Non-parametric Mann-Kendall and Sen's tests performed on TEQs and PCDD/Fs standardized at a mean lake trout length of 60 cm suggest a linearly decreasing trend for PCDD/Fs in lake trout from Lakes Ontario and Huron. There was no monotonously increasing or decreasing trend found for Lake Superior lake trout. The ratios of 2,3,7,8-TCDD to 2,3,7,8-TCDF concentrations were generally constant during the 1989-2003 period with the values being in the order of Lakes Superior (0.05-0.3) <or= Huron (0.16-0.25)<<Ontario (0.56-0.88). These spatial differences observed in the relative abundance of TCDD and TCDF suggest that the sources of dioxins and furans differ between the upper and lower Great Lakes.

Total suspended particulate (TSP), polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) emissions from medical waste incinerators in Antioquia, Colombia

Results of a preliminary survey of particulate and dioxin emissions in combustion gases from hospital waste incinerators in Antioquia-Colombia are presented. Base line data of total suspended particulate (TSP) and polychlorinated dibenzodioxin and dibenzofuran (PCDD/PCDF) emissions in incinerators from health care institutions in Antioquia-Colombia will be used to improve the management of medical waste in the local context. All monitored incinerators are batch operated. TSP exceeds 80 mg Nm(-3) in 8 out of 12 incinerators. Dioxin emissions are in the range from about 7 to 700 I-TEQ (ng Nm(-3)). Such a significant amount of dioxin emissions did correlate with entrained particulate matter, mainly as a consequence of poor control of operation parameters. Several suggestions are made to improve medical waste management practices in Colombia.

Atmospheric concentrations of PCDDs/PCDFs in Metropolitan Hartford Connecticut--current levels and historical data

The State of Connecticut (CT) has established an Ambient Air Quality Standard (AAQS) for PCDDs/PCDFs expressed as 2, 3, 7, 8-TCDD equivalents on an annualized basis of 1.0 pg/m(3) TEQ. This AAQS represents the maximum concentration permitted in ambient air from all known sources of PCDDs/PCDFs including background contributions. Atmospheric concentrations of PCDDs/PCDFs are currently monitored at a single site located in Hartford Connecticut. The data collected at this site are compared annually to the AAQS and ultimately used to demonstrate compliance with the AAQS. Samples were collected at Brainard Airport in Hartford, CT. during each of two winter sampling campaigns. These sampling campaigns that were conducted during the winter months of 2003-2004 and 2004-2005 each consisted of two 30 day sampling events conducted in consecutive fashion. Results are provided for a total of eight (8) samples (reported as pairs) representing a total of four (4) 30 day sampling events. The mean concentration for the eight sample set of 0.013 pg/m(3) TEQ represents 1.4% of the CT DEP (Connecticut Department of Environmental Protection) AAQS guideline of 1.0 pg/m(3) TEQ. The highest values were observed during the January 20-February 18, 2005 sampling event (0.0193 and 0.0204) while the lowest TEQ values were observed during the December 21, 2004-January 20, 2005 sampling event (0.0124 and 0.0127). All measured values were significantly below the AAQS of 1.0 pg/m(3). The mean concentration for total PCDDs/PCDFs (Cl4-Cl8) measured in the eight sample set was 2.62 pg/m(3). This value is higher than concentrations measured historically at other locations in the State of Connecticut including urban settings such as Bridgeport, Wallingford and Hartford. The ambient PCDDs/PCDFs profile for the Brainard Airport Site is consistent with profiles typically attributable to combustion sources. The PCDDs/PCDFs profile is remarkably similar to profiles observed at the majority of sites used by the State of Connecticut during prior PCDDs/PCDFs monitoring programs. Congener profile analyses of samples collected in the Hartford Metropolitan area including most notably samples collected in consecutive winter seasons at the Brainard Airport site suggest a common set of source contributions to PCDDs/PCDFs levels measured in ambient air at these locations.

An integrated approach to assess the PCDD/F emissions of the coal fired stoves combining emission measurements and ambient air levels modelling

Very high emissions of PCDD/Fs up to 1300 microg TEQ per ton of coal were measured during combustion of commercial high chlorine content coal in a stove. A pronounced effect of the temperature profile in the chimney on PCDD/F emissions was identified, suggesting formation in the chimney. Emissions of PCDD/Fs were one order of magnitude higher with an insulated chimney than with a non-insulated one. Insulation of the chimney did not influence the emissions of regulated pollutants and PAHs. Under laboratory conditions, the thermal properties of the chimney usually differ from those in residential dwellings. For that reason it is concluded that PCDD/F emission measurements performed under laboratory conditions may not be representative for derivation of emission factors in emission inventory compilations. Thus the emission factor of 1300 microg TEQ per ton of coal (40000 microg TEQ/TJ) represents the maximum value for individual stove emissions. Complementary air dispersion modelling and congener profile based receptor modelling performed in the Krakow area, Poland confirm a high contribution of the residential combustion to the ambient air PCDD/F levels in that area and indicate an emission factor for coal combustion in stoves in the order of 100 microg TEQ per ton (3000 microg TEQ/TJ).

Numerical modelling of the memory effect in wet scrubbers

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) can be absorbed in and desorbed from polypropylene (PP) tower packings in wet scrubbers utilized in waste incineration lines. This behaviour, also known as the memory effect, has been modelled using a gas phase-PP surface equilibrium and a numerical solid phase diffusion model describing the transport of PCDD/Fs inside the PP. The diffusivities and gas-PP partition coefficients of TCDD/F to HxCDD/Fs in PP have been estimated using the numerical model. Two incineration lines were modelled. In the first line, the absorption and desorption in PP test rods was followed before and after installation of a fabric filter that was placed before a wet scrubber. In the second incineration line, the accumulation of PCDD/Fs in a wet scrubber during start up periods and the subsequent decline during the following three months was modelled and compared to continuous two-week gas measurements after the scrubber. The obtained diffusivities in PP range from 10(-13) m(2)/s for TCDD to 10(-16) m(2)/s for HxCDD. Lower chlorinated homologues with a distinctive change in concentrations during the desorption period (e.g. TCDF) are easier to model, and show the best agreement between the two incineration lines.

Atmospheric input of POPs into Lake Maggiore (Northern Italy): PCDD/F and dioxin-like PCB profiles and fluxes in the atmosphere and aquatic system

The delivery and accumulation of PCDD/Fs and dioxin-like PCBs (DL-PCBs) as recorded in sediments from the Lake Maggiore (LM) in Northern Italy and the influence of the atmosphere in contaminating this subalpine ecosystem were studied. PCDD/Fs (17 congeners) and DL-PCBs (12 congeners) concentrations, congener profiles and fluxes in air, bulk deposition, aquatic settling material and surface sediments are presented. Our strategy was to obtain surface sediment from areas near riverine inputs and in the depositional basins, settling material in sediment traps at one site and air, aerosol and bulk deposition profiles. PCDD/F concentrations in air of 25 WHO-TEQ fg m(-3) and DL-PCBs of 7 WHO-TEQ fg m(-3) were measured. Bulk atmospheric deposition yielded 140 and 28 WHO-TEQ pg m(-2) per week for dioxins/furans and DL-PCBs, respectively. Aquatic settling material exhibited concentrations of 11 WHO-TEQ pg g(-1) for PCDD/Fs and 2 WHO-TEQ pg g(-1) for DL-PCBs. Weekly settling material fluxes of 50 WHO-TEQ pg m(-2) and 10 WHO-TEQ pg m(-2) were obtained for PCDD/Fs and DL-PCBs, respectively. PCDD/Fs concentrations in surface sediments varied from 0.1 to 17 WHO-TEQ pg g(-1) whereas values ranged from 0.03 to 6 WHO-TEQ pg g(-1) for DL-PCBs. The concentrations obtained in the environmental compartments studied suggest a situation of low level contamination. PCDD/Fs and DL-PCBs congener profiles in atmospheric air, bulk deposition, aquatic settling matter and surface sediment point to an important if not dominant contribution from atmospheric deposition to Lake Maggiore, especially derived from wet deposition of aerosol-bound PCDD/Fs and DL-PCBs. Flux estimates support this hypothesis.

Removal of vapour phase PCDD/Fs in electric arc furnace steelmaking emissions by sorption using plastics

Plastics are potentially suitable for the removal of vapour phase PCDD/Fs in emissions from the electric arc furnace (EAF) steelmaking process. Three different commercial plastics, i.e. polypropylene BE170MO (Borealis A/S, Denmark), polypropylene in the form of 5 mm spheres (The Precision Plastic Ball Co. Ltd., UK) and polyethylene LD605BA (ExxonMobil Chemical, Belgium), have been studied using a novel experimental apparatus for the removal of vapour phase PCDD/Fs. Polypropylene BE170MO was identified to be the most suitable product amongst the three plastics in terms of PCDD/F sorption and potential industrial application. The optimum temperature for PCDD/F sorption on polypropylene BE170MO was below 90 degrees C for a removal efficiency of >99% at an average vapour phase PCDD/F concentration of 3.5 ng I-TEQ/Nm(3). At 130 degrees C, 53% of the PCDD/Fs trapped on polypropylene BE170MO were desorbed.

[New method of multi-components quantitation by one marker new method for quality evaluation of Guanmaikang capsula]

OBJECTIVE

To establish a new quality evaluation method for traditional Chinese medicine preparations, using one chemical reference substance to calcutate multi-components simultaneously.

METHOD

Employed puerarin as the maker component, puerarin relative correction factors (RCF) of salvianolic acid B to puerarin and paidzein to puerarin were calcatated in the chromatographic conditions for determination of the three components in Guanmaikang capsules. The contents of Puerarin were determined by external standard method, and those of salvianolic acid B and paidzein were calculated by puerarin and their RCF. The accuracy of the new method was evaluated by comparing the calculated contents with the determined.

RESULT

The analysis methods were established, and it has been no significant difference between the calculated contents and determined contents.

CONCLUSIONS

The method can control the components without providing salvianolic acid B and paidzein reference. It is to be a suitable quality evaluation pattern for TCM Preparation.

Declining polychlorinated dibenzo-p-dioxins and dibenzofurans levels in the sediments from Dongting Lake in China

Dongting Lake is the second largest freshwater lake in China. Technical sodium pentachlorophenate (Na-PCP) had been sprayed since 1960s to control the spread of snailborne schistosomiasis up to the middle of 1990s. As one of the by-products of Na-PCP, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may enter the environment. It has been reported that the concentrations of PCDD/Fs in sediments in Dongting Lake were 130-891 pg I-TEQ g(-1) in 1995. High toxicity of sediment to exposed microorganisms and fish may be risk on environment. In order to determine the present levels of the contamination, eight sediment samples from Dongting Lake were analyzed for PCDD/Fs using HRGC-HRMS. Total I-TEQ values for these samples were at a ranged of 0.7-11 pg g(-1), with a mean value of 4.5 pg g(-1). The results show that PCDD/Fs concentrations of contemporary sediment have declined since 1995. Certain PCDD/F congeners as well as OCDD, typical for Na-PCP, predominated in lake sediment indicating that the using of PCP-Na is the main source of PCDD/Fs in the lake. These variations in levels can reflect changes in PCDD/F sources to the environment over time.

Determining optimal operation parameters for reducing PCDD/F emissions (I-TEQ values) from the iron ore sintering process by using the Taguchi experimental design

This study is the first one using the Taguchi experimental design to identify the optimal operating condition for reducing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) formations during the iron ore sintering process. Four operating parameters, including the water content (Wc; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (including sinter, hematite, and limonite), were selected for conducting experiments in a pilot scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant We found that the resultant optimal combination (Wc = 6.5 wt%, Hb = 500 mm, Ps = 1000 mmH2O, and hearth layer = hematite) could decrease the emission factor of total PCDD/Fs (total EF(PCDD/Fs)) up to 62.8% by reference to the current operating condition of the real-scale sinter plant (Wc = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH2O, and hearth layer = sinter). Through the ANOVA analysis, we found that Wc was the most significant parameter in determining total EF(PCDD/Fs (accounting for 74.7% of the total contribution of the four selected parameters). The resultant optimal combination could also enhance slightly in both sinter productivity and sinter strength (30.3 t/m2/day and 72.4%, respectively) by reference to those obtained from the reference operating condition (29.9 t/m (2)/day and 72.2%, respectively). The above results further ensure the applicability of the obtained optimal combination for the real-scale sinter production without interfering its sinter productivity and sinter strength.

Protective effects of dihydroxylphenyl lactic acid and salvianolic acid B on LPS-induced mesenteric microcirculatory disturbance in rats

Salvia miltiorrhiza is a Chinese medicine widely used for treatment of various cardiovascular diseases. However, little is known about the role of dihydroxylphenyl lactic acid (DLA) and salvianolic acid B (SAB), the main ingredients of S. miltiorrhiza, in the microcirculation. This study aimed to investigate the effect of DLA and SAB on LPS-elicited microcirculatory disturbance, focusing especially on leukocyte adhesion and its potential mechanism. Mesenteric venular diameter, velocity of red blood cells in venules, shear rate of the venular wall, numbers of leukocytes adherent to and emigrated across the venular wall, and mast cell degranulation were determined by an inverted microscope in rats after LPS infusion with or without DLA or SAB. Expression of CD11b and CD18 and production of superoxide anion (*O2-) and hydrogen peroxide (H2O2) by neutrophils were evaluated in vitro by flow cytometry. LPS exposure induced a significant increase in the number of adherent and emigrated leukocytes and mast cell degranulation, and a prominent decrease in the velocity of red blood cells in venules and shear rate of the venular wall. Additionally, in vitro experiments revealed an apparent enhancement in expression of CD11b and CD18 and production of *O2- and H2O2 by rat neutrophils by LPS stimulation. Treatment with DLA or SAB significantly ameliorated LPS-induced microcirculatory disturbance in rat mesentery and inhibited both the expression of CD11b and CD18 and the production of *O2- and H2O2 by neutrophils caused by LPS.

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in blood and breast milk collected from 60 mothers in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho polychlorinated biphenyls (non-ortho PCBs), and mono-ortho polychlorinated biphenyls (mono-ortho PCBs) in paired samples of blood and breast milk collected from 60 mothers in Sapporo City, Hokkaido Prefecture, Japan. The present study is one of the few studies in which PCDDs, PCDFs, and dioxin-like PCBs have been measured in blood and breast milk collected from 60 same mothers. Of these 60 mothers, 30 were primipara (mean: 30.1 years, median: 28.0 years) and 30 were multipara (mean: 32.2 years, median: 32.5 years). The arithmetic mean TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the primiparous mothers were 9.0, 3.3, 5.7, and 0.4 pg TEQ g(-1) lipid, respectively, and 5.2, 2.2, 4.5, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations of these dioxin-like compounds being 9.3-42.9 (mean: 18.4, median: 17.3) and 7.0-41.1 (mean: 12.3, median: 11.4) pg TEQ g(-1) lipid, respectively. In the case of multiparous mothers, the arithmetic mean TEQ concentrations of these dioxin-like compounds in blood and breast milk were 7.1, 2.7, 5.3, and 0.4 pg TEQ g(-1) lipid, respectively, and 3.9, 1.7, 3.8, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations being 3.4-28.1 (mean: 15.5, median: 13.9) and 2.7-20.0 (mean: 9.8, median: 9.2)pg TEQ g(-1) lipid, respectively. The total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of primiparous mothers in Sapporo City appeared to be generally lower than those recently surveyed throughout the greater area of Japan. Significant correlations were observed between age and the total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in the blood of primiparae and multiparae, and significant correlations were also observed between age and the total TEQ concentrations of these dioxin-like compounds in the breast milk of primiparae and multiparae. The total TEQ concentrations of PCDDs, PCDFs, and dioxin-like PCBs in the blood of primiparous mothers showed a close correlation to those in their breast milk and also showed good correlations between the total TEQ concentrations of these dioxin-like compounds in the blood of multiparous mothers and those in their breast milk. The result of a comparison of the arithmetic mean concentrations of each congener of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk indicated that the transfer of octachlorodibenzo-p-dioxin (OCDD) from the blood to the breast milk was lower than those of other congeners. In contrast, among mono-ortho PCBs congeners, the arithmetic mean concentrations of 2,3',4,4',5-pentachlorobiphenyl (PentaCB) (#118) and 2,3,3',4,4'-PentaCB (#105) in the breast milk were slightly higher than those in the blood, which suggested that breast-fed infants may be at higher risk from mono-ortho PCBs.

Benzofuran derivatives from the mangrove endophytic Fungus Xylaria sp. (#2508)

Three metabolites, named xyloketal J (1), xyloester A (2), and xyloallenolide B (3), together with the known substituted dihydrobenzofuran (4) were isolated from the mangrove endophytic fungus Xylaria sp. (#2508). Structures were determined by spectroscopic methods, mainly 1D and 2D NMR.

Constituents of the root wood of Zanthoxylum wutaiense with antitubercular activity

Bioassay-guided fractionation of the root wood of Zanthoxylum wutaiense led to the isolation of 11 new compounds, wutaiensol methyl ether (1), demethoxywutaiensol methyl ether (2), methyl wutaiensate (3), methyl 7-hydroxyanodendroate (4), methyl 7-methoxyanodendroate (5), wutaifuranol (6), 7-methoxywutaifuranol (7), 7-methoxywutaifuranal (8), methyl wutaifuranate (9), methyl 7-methoxybenzofuran-5-carboxylate (10), and wutaipyranol (12), together with another 37 known compounds, of which one, 7-methoxybenzofuran-5-carboxaldehyde (11), was not previously known as a plant constituent. The structures of these isolates were identified by means of spectroscopic analysis. Five of these isolates were found to be antitubercular constituents, namely, methyl 7-methoxyanodendroate (5), 7-methoxywutaifuranal (8), wutaiensal (13), dictamnine (14), and gamma-fagarine (15), which exhibited antitubercular activity against Mycobacterium tuberculosis H37Rv, showing MIC values of 35, 35, 30, 30, and 30 microg/mL, respectively.

Characterization of compounds from the roots of Saposhnikovia divaricata by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

In this study, four types of compounds including coumarins, chromones, furoylmethyl amino acid derivative and benzofuran glycoside were isolated from the roots of Saposhnikovia divaricata. The electrospray ionization (ESI) mass spectral fragmentation pathways of these compounds were proposed. In particular, the ESI-MS(n) fragmentation behavior of linear dihydrofurocoumarins, dihydrofuro- and dihydropyranochromones were deduced in detail. For the linear dihydrofurocoumarins, the fragmentation was triggered by the initial loss of the C-4' substituting group. Then, the characteristic ions were observed followed by the losses of 15, 18, 28 and 46 Da. It is noteworthy that the elimination of H(2)O (18 Da) from the cleavage of the dihydrofuran ring is reported for the first time. For the linear dihydrofurochromones, characteristic eliminations of 18, 48 and 72 Da were observed. The loss of 18 Da could arise from two different fragmentation pathways, and the observed ion was composed of a mixture of two different structural ions. For the linear dihydropyranochromones, it was found that the dihydropyran ring was converted into the pyran ring by the elimination of the C-3' substituting group. This fragmentation was followed by the diagnostic losses of 18, 28, 42 and 54 Da in tandem mass spectrometry. The above fragmentation rules were successfully applied for the analysis of the chemical constituents of the roots of Saposhnikovia divaricata. A total of 32 compounds were identified or tentatively characterized by HPLC/DAD/ESI-MS(n). Among them, eight compounds were new and seven compounds were reported from that genus for the first time.

Phytochemical investigation of Anaphalis lactea

Four new compounds, 2',6'-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-4'-methoxychalcone ( 1), 4,6-dihydroxy-7-isobutyryl-5-prenyl-2(3 H)-benzofuranone ( 4), 7- O-(beta- D-glucopyranosyloxy)-5-hydroxy-1(3 H)-isobenzofuranone ( 6) and (2 R,3 S)-3-methyl-2-(5-oxo-2-isopropenylhexyl)-cyclopentanone ( 7), along with thirteen known compounds were isolated from the whole plant of Anaphalis lactea. Their structures were established based on spectroscopic methods including IR, UV, MS, CD, 1 D NMR and 2 D NMR techniques. Compounds 2, 4 - 6 and 8 - 16 were tested for free-radical scavenging properties in the DPPH assays.

Highly sensitive and selective spectrophotometric and spectrofluorimetric methods for the determination of ropinirole hydrochloride in tablets

Three sensitive, selective, accurate spectrophotometric and spectrofluorimetric methods have been developed for the determination of ropinirole hydrochloride in tablets. The first method was based on measuring the absorbance of drug solution in methanol at 250 nm. The Beer's law was obeyed in the concentration range 2.5-24 microg ml(-1). The second method was based on the charge transfer reaction of drug, as n-electron donor with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as pi-acceptor in acetonitrile to give radical anions that are measured at 842 nm. The Beer's law was obeyed in the concentration range 0.6-8 microg ml(-1). The third method was based on derivatization reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 8.5 followed by measuring the fluorescence intensity at 525 nm with excitation at 464 nm in chloroform. Beer's law was obeyed in the concentration range 0.01-1.3 microg ml(-1). The derivatization reaction product of drug with NBD-Cl was characterized by IR, 1H NMR and mass spectroscopy. The developed methods were validated. The following analytical parameters were investigated: the molar absorptivity (epsilon), limit of detection (LOD, microg ml(-1)) and limit of quantitation (LOQ, microg ml(-1)), precision, accuracy, recovery, and Sandell's sensitivity. Selectivity was validated by subjecting stock solution of ropinirole to acidic, basic, oxidative, and thermal degradation. No interference was observed from common excipients present in formulations. The proposed methods were successfully applied for determination of drug in tablets. The results of these proposed methods were compared with each other statistically.

Antioxidant 2-phenylbenzofurans and a coumestan from Lespedeza virgata

Two 2-phenylbenzofurans, lespedezavirgatol (1) and lespedezavirgatal (2), and a coumestan, lespedezacoumestan (3), were isolated from the aerial parts of Lespedeza virgata, together with nine known flavonoids. Their structures were determined on the basis of spectroscopic data. The three new compounds showed strong oxygen radical absorbance capacity and potent inhibition toward lipid peroxidation in both plasma and kidney homogenate of renal failure rats.

Removal characteristics of PCDD/Fs by the dual bag filter system of a fly ash treatment plant

In this study, a dual bag filter system was established to decrease the concentration of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in the stack flue gases of a fly ash treatment plant, which retained zinc from the fly ash of electric arc furnaces. Compared to the original single bag filter system with activated carbon injection (ACI) of 40 kg h(-1), the PCDD/F concentrations in the stack flue gas after the plant was equipped with the dual bag filter system dropped enormously from 3.38-7.73 ng I-TEQNm(-3) to 0.03 ng I-TEQNm(-3), and the total PCDD/F I-TEQ removal efficiency increased from 97.6% to 99.3% with ACI of 16 kg h(-1), that is, about 40% of the original AC usage. The AC utilization efficiency (0.560 mg I-TEQ absorbed kg ACI(-1)) of the dual bag filter system (AC: 16 kg h(-1)) was estimated about three times higher than that (0.192 mg I-TEQ absorbed kg ACI(-1)) of single bag filter system with ACI (40 kg h(-1)). The reason is that the particulate phase PCDD/Fs and some gas phase PCDD/Fs (captured by the recycled AC/ash mixture) were removed first by the first bag filter, and the rest of the gas phase PCDD/Fs were able to be adsorbed more completely by the AC/ash mixture due to a lower fly ash load, and then were removed by the second bag filter.

Aurocitrin and related polyketide metabolites from the wood-decay fungus Hypocrea sp. BCC 14122

The known gentisaldehyde antibiotic aurocitrin (1), its cis-olefinic isomer (2), a salicylaldehyde analogue (3), two new benzofuran derivatives (4 and 5), and a new dihydroisocoumarin (6) were isolated from the wood-decay fungus Hypocrea sp. BCC 14122. The structures were elucidated primarily by NMR and mass spectroscopic analyses.

[QSPR study on the lipid-water partition coefficients of dioxins based on DFT]

With computational method of density functional theory (DFT), quantified model study of equilibrium partitioning properties of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) between lipid phase of organism (Poecilia reticulata) and water phase was carried out based on quantum chemical and further calculated parameters, namely frontier orbital energies, entropies, traceless quadrupole moments as well as molecular absolute hardness, electronegativities and electrophilicity indices, which all were derived from full geometry optimization of PCDD/Fs. Through multiple linear regression (MLR) analyses, quantitative structure-property relationship (QSPR) was successfully proposed in the form of multi-parameter quadratic function: lgK(hw) = 5.343 - 0.001(S - 125.480)(2) - 0.355(omega - 3.239)(2) + 0.006( Q = - 2.950)(2) - 22.728(eta - 2.365)(2). It was shown that the obtained QSPR had higher goodness of fitting and robustness, determination coefficient and cross-validated correlation coefficient being 0.943 and 0.908 respectively, and it was also provided with ideal interior and exterior predictive abilities so that it could be used for prediction of unknown lipid-water partitioning properties. By comparison, QSPR in this research was superior to that from previous SOFA (solubility parameter for fate analysis) method on the whole. Lipid-water partitioning properties (coefficients) of PCDD/Fs should be mainly related to molecular volume and aryl hydrocarbon molecular interactions determined by charge distribution. To a certain degree, they also might be influenced by potential biotransformation and molecular reactivity.