Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China

In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard-hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November-December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non-methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH-containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/ trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non-existent emission treatment, but were much more influenced by the FC. © 2012. American Geophysical Union. All Rights Reserved

Determination of speciation of elements related to blood sugar in bioactive extracts from Cyclocarya paliurus leaves by FIA-ICP-MS

This paper describes the development and application of FIA-ICP-MS technique for the speciation of trace elements in extracts of Cyclocarya Paliurus (Batal.) Iljinsk (CP) leaves, an herbal tea used widely in China as dietary supplement for Elements Related to Blood Sugar (ERBS), which are reported to have the beneficial effects of lowering blood sugar. Most ERBSs are found to be water-soluble. On the basis of elemental distribution, the aqueous solutions of CP of different origins can be separated into two groups: one is rich in organo-magnesium, organo-manganese, organo-zinc, inorganic copper, and inorganic nickel; while the other is rich in inorganic magnesium, inorganic manganese, inorganic copper, inorganic nickel and organo-zinc. The ERBSs in two bioactive extracts of CP named EE and POLY were analyzed and compared, and the results suggest that the extracts are good dietary supplement for people, especially Diabetes Mellitus (DM) patients through the provision of ERBSs of Mn, Zn, Mg, Cu, and Ni in organic or inorganic forms

Isolation and purification of inflacoumarin A and licochalcone A from licorice by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been applied to isolate and purify bioactive flavone compounds from the ethanol extract of Glycyrrhiza inflata Bat., a particular plant species of licorice. HSCCC separation was performed with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (5:6:3:2, v/v) by eluting the lower mobile phase at a flow rate of 1.8 ml/min and a revolution speed of 800 rpm. Purification was performed with a two-phase solvent system composed of n-hexane-chlorofonn-methanol-water (1.5:6:3:2, v/v) by eluting the lower mobile phase at a flow-rate of 1.5 ml/min and a revolution speed of 800 rpm. Two major flavone peaks: inflacoumarin A and licochalcone A were collected and the respective yields of the peaks amount to 6 mg (8.6%, w/w) and 8 mg (11.4%, w/w) from 70 mg of the crude extract sample. The purities of inflacoumarin A and licochalcone A reached 99.6% and 99.1%, respectively, after a sequential purification run. The structures of inflacoumarin A and licochalcone A were positively confirmed by H-1 NMR and C-13 NMR, H-1-C-13-COSY, UV, FR-IR and electron ionization MS analyses. (C) 2004 Elsevier B.V. All rights reserved

Pyrolysis coupled with atomic absorption spectrometry for the determination of mercury in Chinese medicinal materials

A pyrolysis unit was coupled to an atomic absorption spectrometer for the determination of mercury in solid samples of Chinese medicinal materials (CMMs). This highly sensitive analytical technique provides a simple and rapid method for the screening of Hg in CMM samples including raw herbs, mineral drugs and their derived formulated products. Only 20 mg samples were needed and the sensitivity is down to 66 pg. The precisions of analyzing solid Hg standard samples and real CM samples were 1.9 and 3-7%, respectively. The recovery of the method was between 97.6 and 102.7% using Hg standard spiked certified reference material of Apple Leaves. No sample pre-treatment was needed and this greatly simplifies the analytical procedure and minimizes potential sources of contamination. Several CM samples were analyzed and the results obtained agreed well with the certified values. The performance of the method was compared with the widely used cold vapor and inductively coupled plasma-mass spectrometry (ICP-MS) methods. Excellent agreements were observed among these methods for Hg levels in the ng region. With the temperature programming capability of the pyrolysis chamber the instrument can potentially be used for the speciation analysis of Hg. (C) 2001 Elsevier Science B.V. All rights reserved

Development of sampling techniques for trace organic pollutants in water - Analysis of PAHs in water by PUF

The article reports the application of PUF (polyurethane foam) for PAHs sampling in water. The technique is found to be suitable for the sampling of PAHs and other trace organics in different water samples. The DL(detection limit) for pyrene-d10 in 1 L water is 26 ng/L when GC/MS is used for analysis. Much lower MDLs can be achieved when HPLC-Fluorescence is used for PAH analysis. The observed MDLs for benzo (k) fluoranthene, benzo (a)pyrene, dibenz (a,h) anthracene and benzo(ghi)perylene in 1 L water are 0.86, 0.56, 2.1, 3.0 ng/L respectively. HPLC-Fluorescence analysis also gives very litter background interference by PUF. PUF sampling coupled with HPLC-fluorescence analysis is therefore promising method for the measurement of ultratrace levels of PAHs in aquatic environment

Determination of arsenic and antimony by microwave plasma atomic emission spectrometry coupled with hydride generation and a PTFE membrane separator

The performance of a microwave plasma torch (MPT) discharge atomic emission spectrometry (AES) system directly coupled with hydride generation (HG) for the determination of As and Sb has been studied. The argon MPT system can sustain a stable plasma over a wide range of carrier and support gas flow rates with optimum performance at 250 and 1450 ml min(-1), respectively. The presence of trace amount of water in the MPT discharge is found to affect the detection limits and the signal to noise ratio. A PTFE membrane separator is applied for hydride introduction and water rejection. In addition, the membrane cell separator also improves the signal to noise ratio by serving as a pressure buffer to minimize noise due to pressure fluctuation. Detection limits (3 sigma) of 8.1 and 3.2 ng ml(-1) are obtained with the analytical lines As I 228.812 nm and Sb I 259.809 nm, respectively at an MPT power of 135 W. The detection limits are improved when a concentrated sulfuric acid cell is placed after the membrane cell to further remove water. This double cell system yields detection limits of 5.3 and 2.1 ng ml(-1) for As and Sb, respectively under the same operating conditions. Linear dynamic ranges of three orders of magnitude could be obtained. (C) 2001 Elsevier Science B.V. All rights reserved

A capsule review of recent studies on the application of mass spectrometry in the analysis of Chinese medicinal herbs

Chinese herbal medicine is gaining increasing popularity worldwide as an alternative approach to the development of pharmaceuticals in therapeutic applications. Chemical characterization and compositional analysis of Chinese medicines provide the necessary scientific basis for the discovery and development of new drugs of natural origin. Applications of mass spectrometry in the analysis of Chinese herbal medicines have been growing rapidly in recent years owing to the rapid technical advances and increasing availability of the instrumentation. This paper reviews the current status of how different mass spectrometric techniques are being used to support research studies of Chinese medicines. The focus is on crude herbal medicines and their derived products. The review is not meant to be exhaustive, but rather to provide a general overview of the various research activities in this rapidly expanding field. In the discussion of specific herbs, the emphasis is placed on ginseng and Danshen, two of the herbs for which active experimental work is on-going in the authors' laboratories. Other selected herbs will be discussed only briefly, aiming primarily to illustrate the current status of research in the area. Copyright (C) 2002 John Wiley Sons, Ltd

Quantitative analysis by solid-phase microextraction in nonequilibrium situations - Rapid determination of pollutant compounds (PAHs) in water

Solid-phase microextraction technique has the advantages of a high efficiency, sensitivity, simple operation and solvent free. An optical fiber coated with 100 mu m polydimethylsiloxane is used to extract 10 PAHs. Since the absorption rate is stable within 60 min before equilibrium, the quantitative analysis may be realized in nonequilibrium situations. The linear concentrations range from 0.1 mu g/L to 100 mu g/L, the detection limits are in the range of 0. 01-0. 03 mu g/L, the recoveries are within 80% and 100%, and relative standard deviatants are below 20% for these PAHs

Source identification of Salvia Miltiorrhiza BUNGE (Danshen) by lead isotope ratios

The hyphenated technique of flow injection, and inductively coupled plasma-mass spectrometry (ICP-MS) system with micro-column was established. Based on the analytical method, lead isotope ratios of Danshen could be accurately measured. The trace lead in the sample was concentrated and the matrix was removed on-line. Precision of the measurement was tested. The results show that the relative standard deviations (RSD%), meet the analytical requirement. For Danshen of the same area the lead isotope ratios are similar, but they are different for the samples from different sources. So the isotope ratios can be used to identify the sources of the Chinese medicines