Xiaofang Fu

Characteristics of polycyclic aromatic hydrocarbons in agricultural soils at a typical coke production base in Shanxi, China ☆

There is wide concern about polycyclic aromatic hydrocarbons (PAHs) because of their carcinogenic and mutagenic potential. The coking industry is an important source of PAHs. In this study, 36 arable soil samples, a sensitive medium from the perspective of food safety and health, were collected from one of the largest coke production bases in China. The concentration of total 21 PAHs ranged from 294 to 1665 ng g(-1), with a mean of 822±355 ng g(-1). Approximately 60% of the soil samples were heavily polluted with the level higher than 600 ng g(-1). Particularly high abundances of high molecular weight PAHs were found, and the calculated BaPeq was as high as 54.3 ng g(-1). Soil PAH levels were positively correlated with soil organic matter content. The soil PAHs were from complex mixture sources, and high-temperature pyrogenic sources were most likely responsible for the heavy PAH contamination. Effective control strategies and probable remediation approaches should be proposed to improve soil quality.

Analysis of aristolochic acids by CE-MS with carboxymethyl chitosan-coated capillary.

A CE‐MS method for rapid determination of aristolochic acid‐I and aristolochic acid‐II (AA‐II) in traditional Chinese medicines and biological samples was described in the present paper. AA‐I and AA‐II can be baseline separated within 6 min by CE‐MS with carboxymethyl‐chitosan‐coated capillary. CZE conditions including pH, concentration of buffer, applied voltage, and capillary temperature were systematically investigated, and the composition and flow rate of sheath liquid were also optimized for CE‐MS. Furthermore, the CE‐UV method without any additives in BGE solution was established and compared with the CE‐MS method. The results showed that the two methods could achieve satisfactory separation efficiency, repeatability, and linearity, while the LOD was 0.6 μg/mL for CE‐UV and 0.05 μg/mL for CE‐MS. Compared with the CE‐UV method, the sensitivity of CE‐MS was significantly improved, in addition to the structure information provided by MS detection at the same time. As an application example, a spiked sample in human serum was analyzed by the CE‐MS method, indicating that the new CE‐MS method can be applied to analyze AAs in biological samples.

Determination of dissociation constants of aristolochic acid I and II by capillary electrophoresis with carboxymethyl chitosan-coated capillary

Aristolochic acid-I and aristolochic acid-II have been proved to be the main bioactive and toxic component in Aristolochia plants. As a result, the determination of their dissociation constants, which are important property parameters for weak acids, is highly desired for related pharmacological and toxicological studies. In this work, the dissociation constant values of aristolochic acid-I and aristolochic acid-II were determined by capillary electrophoresis using carboxymethyl chitosan-coated capillary, based on their electrophoretic mobilities by using nonlinear regression as well as linear regression, showing that the two models give comparable results. The data were also compared with those obtained by capillary electrophoresis with polybrene-coated capillary, and no conspicuous difference was observed. The correlation coefficients were all higher than 0.998 for both linear and nonlinear regression model. The pKa values were found to be 3.3±0.1 for aristolochic acid-I and 3.2±0.1 for aristolochic acid-II.

Application of Chitosan and Its Derivatives in Analytical Chemistry: A Mini-Review

Recent progress in the application of chitosan and its derivatives in analytical chemistry, especially their application in the field of separation science including as capillary coating materials, chromatographic column fillings, and adsorption materials, during the past 8 years is reviewed.

Can Coronene and/or Benzo(a)pyrene/Coronene ratio act as unique markers for vehicle emission?

Coronene is a high molecular weight polycyclic aromatic hydrocarbon with seven aromatic rings. It, more specifically a lower ratio of Benzo[a]pyrene to Coronone (BaP/COR), is suggested as a marker for vehicle emission. In the present study, emissions of Coronene were measured from residential combustions of wood, crop straw, and pellets. The detection of COR in non-vehicle emission sources, and comparable BaP/COR ratios between the solid fuel combustion and vehicle emissions indicated that the generality of COR or the BaP/COR ratio as markers for the vehicle emission would be questionable, especially for the area where solid fuel combustion dominated the PAHs emission.

Comparison and Analysis of Organochlorine Pesticides and Hexabromobiphenyls in Environmental Samples by Gas Chromatography–Electron Capture Detector and Gas Chromatography–Mass Spectrometry

Two analytical methods, gas chromatography-electron capture detector (GC-ECD) and gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS), were evaluated and compared for the measurement of persistent organic pollutants, specifically for 26 organochlorine pesticides and two hexabromobiphenyls, in atmospheric particulate matter and soil samples. The hypothesis tested was that the coelution of non-target compounds may lead to false positives when analyzed by GC-ECD, and that the overestimation associated with these false positives can be eliminated using GC-NCI-MS. The study showed that both methods had satisfactory linearity and reproducibility for the target compounds. Although the sensitivities of GC-ECD for most of the compounds investigated were higher than those observed with the GC-NCI-MS method, the matrices interference was obvious with GC-ECD. There was indeed an apparently high false-positive rate or overestimate when GC-ECD was used for environmental samples, implying that the GC-ECD method has been used with care and that GC-NCI-MS is generally superior for the analysis of trace amounts of these compounds in environmental samples. Based on these results, the sample extraction and cleanup procedures of the GC-NCI-MS method were optimized for achieving acceptable recoveries and less matrices interference.

Rapid and subnanomolar assay of recombinant human erythropoietin by capillary electrophoresis using NanoOrange precolumn labeling and laser‐induced fluorescence detection

Because of less functionally critical carbohydrate sectors that contributed to the stability, efforts have been made to quantify intact recombinant human erythropoietin. A simple, rapid capillary electrophoresis with laser-induced fluorescence method for the assay of recombinant human erythropoietin was developed, with a limit of detection of intact recombinant human erythropoietin at subnanomolar concentration (up to 10 ng/mL or 3 × 10(-10) M), which is among the lowest reported. High sensitivity was accomplished by precolumn derivatization with the noncovalent dye NanoOrange. Capillary electrophoresis separation and reaction conditions were carefully manipulated for avoiding microheterogeneity of glycoforms and inhomogeneity of multiple labeling products. The fluorescence signal was linear over the range of 10 ng/mL-10 μg/mL, corresponding to the detection requirement of recombinant human erythropoietin in biofluids and pharmaceutical samples, as demonstrated by a real sample analysis. Although the salt in reaction mixtures showed a detrimental effect on the fluorescence of the derivatives, this method could tolerate a certain amount of salt, extending its application in biofluid analysis. In addition, zero-order fluorescence emission kinetics was obtained, indicating that the rapid decay of recombinant human erythropoietin was derived from a self-quenching effect.

Air pollution and inhalation exposure to particulate matter of different sizes in rural households using improved stoves in central China

Household air pollution is considered to be among the top environmental risks in China. To examine the performance of improved stoves for reduction of indoor particulate matter (PM) emission and exposure in rural households, individual inhalation exposure to size-resolved PM was investigated using personal portable samplers carried by residents using wood gasifier stoves or improved coal stoves in a rural county in Central China. Concentrations of PM with different sizes in stationary indoor and outdoor air were also monitored at paired sites. The stationary concentrations of size-resolved PM in indoor air were greater than those in outdoor air, especially finer particles PM0.25. The daily averaged exposure concentrations of PM0.25, PM1.0, PM2.5 and total suspended particle for all the surveyed residents were 74.4±41.1, 159.3±74.3, 176.7±78.1 and 217.9±78.1μg/m3, respectively. Even using the improved stoves, the individual exposure to indoor PM far exceeded the air quality guideline by WHO at 25μg/m3. Submicron particles PM1.0 were the dominant PM fraction for personal exposure and indoor and outdoor air. Personal exposure exhibited a closer correlation with indoor PM concentrations than that for outdoor concentrations. Both inhalation exposure and indoor air PM concentrations in the rural households with gasifier firewood stoves were evidently lower than the reported results using traditional firewood stoves. However, local governments in the studied rural areas should exercise caution when widely and hastily promoting gasifier firewood stoves in place of improved coal stoves, due to the higher PM levels in indoor and outdoor air and personal inhaled exposure.