Ecological Risk Assessment and Source Identification of Heavy Metals in Soils from Shiyang River Watershed in Northwest China.

Shiyang River Watershed is an important ecological barrier and agricultural production area in Northwest China, and the study of soil heavy metal content, distribution, and sources is important for agricultural product safety, pollution control, and ecosystem health. In this paper, 140 soil samples were collected from 28 stations to assess the level of heavy metal (Arsenic (As), Copper (Cu), Lead (Pb), Cadmium (Cd), Chromium (Cr), Mercury (Hg), Nickel (Ni), Zinc (Zn)) contamination, pollutant sources and influencing factors of soil in Shiyang River Watershed through determination of the metal contents and statistical analysis. The results indicated that the soils in the study area are typical saline soils in arid zones. The enrichment factors (EF) of As, Cr, Cu, Ni, Zn, and Pb indicate no contamination, and the EFs of Cd and Hg suggested minor contamination. Although the concentrations of Cd and Hg in soil are lower than others, they are more biotoxic and exhibit a moderate-high ecological risk. The index of geoaccumulation (Igeo) values reflect that most of the stations, especially the three groups of samples from depths of 10-20 cm, 20-40 cm, and 40-80 cm, are below the contamination threshold for all heavy metals. The chemical speciation of heavy metals, principal component analysis, and correlation analysis showed that Cr, Cu, Pb, Cd, Ni, and Zn mainly come from the natural accumulation upon weathering of soil-forming matrices. Hg and As mainly come from anthropogenic contributions. The effect of agricultural crop cultivation on soil heavy metal contamination is mainly through farm irrigation and crop-soil interactions, which accelerate the release of heavy metals through the weathering of soil-forming parent material and irrigation, which transports the heavy metals below the surface. The results of this study can provide a scientific basis for the involved authorities to formulate reasonable policies on environmental protection and pollution control.

An ultra-robust fingerprinting method for quality assessment of traditional Chinese medicine using multiple reaction monitoring mass spectrometry.

Chromatographic fingerprinting has been perceived as an essential tool for assessing quality and chemical equivalence of traditional Chinese medicine. However, this pattern-oriented approach still has some weak points in terms of chemical coverage and robustness. In this work, we proposed a multiple reaction monitoring (MRM)-based fingerprinting method in which approximately 100 constituents were simultaneously detected for quality assessment. The derivative MRM approach was employed to rapidly design MRM transitions independent of chemical standards, based on which the large-scale fingerprinting method was efficiently established. This approach was exemplified on QiShenYiQi Pill (QSYQ), a traditional Chinese medicine-derived drug product, and its robustness was systematically evaluated by four indices: clustering analysis by principal component analysis, similarity analysis by the congruence coefficient, the number of separated peaks, and the peak area proportion of separated peaks. Compared with conventional ultraviolet-based fingerprints, the MRM fingerprints provided not only better discriminatory capacity for the tested normal/abnormal QSYQ samples, but also higher robustness under different chromatographic conditions (i.e., flow rate, apparent pH, column temperature, and column). The result also showed for such large-scale fingerprints including a large number of peaks, the angle cosine measure after min-max normalization was more suitable for setting a decision criterion than the unnormalized algorithm. This proof-of-concept application gives evidence that combining MRM technique with proper similarity analysis metrices can provide a highly sensitive, robust and comprehensive analytical approach for quality assessment of traditional Chinese medicine.

[Pollution Characteristics and Risk Assessment of Antibiotics in Lianhua Reservoir].

Thirteen typical antibiotics in surface water of the Lianhua Reservoir were analyzed using HPLC/MS/MS to assess the pollution characteristics and risk levels. Ten antibiotics except for erythromycin, sulfadiazine, and sulfamethoxazole were detected in surface water and the total concentration of antibiotics varied between non-detectable (n.d.) and 925.26 ng ·L-1. Azithromycin had the highest concentration (n.d.-232.61 ng ·L-1) with the detection frequency of 75%, followed by enrofloxacin (n.d.-187.69 ng ·L-1), tetracycline (n.d.-155.05 ng ·L-1), and ciprofloxacin (n.d.-83.66 ng ·L-1) with the detection frequencies over 60%. The spatial distribution of antibiotics was as follows: total concentration of upstream (sampling point 1) > Aoxi River stream tributary (sampling point 2) > reservoir downstream (sampling point 3) > reservoir entrance (sampling point 4) > reservoir area (sampling point 5). The seasonal variations in the concentrations of antibiotics were evident; total concentrations in the dry season were significantly higher than those in the wet and normal seasons. The results of the environmental risk assessment indicated that ofloxacin, enrofloxacin, and ciprofloxacin pose significant risks to the environment. In the Lianhua Reservoir, ciprofloxacin showed high potential risk to the ecological environment, while the environmental risks of other antibiotics in the reservoir were below the medium level. The combined risk value of the antibiotics in the dry season was higher than that in the wet and normal seasons.

Synergistic design of electric field and membrane in facilitating continuous adsorption for cleanup and enrichment of proteins in direct ESI-MS analysis.

We designed and fabricated a novel microdevice to facilitate continuous adsorption phenomena for biological sample preparation. Using the device, we also developed an online, highly integrated, multifunctional strategy, with a promise of accepting a large volume of crude tissue extracts with the end point generation of a reliable MS identification within 20 min. Under an external electric field, charged membranes can adsorb multiple layers of proteins, which exceed the capacity limit of common resins or membranes. It enlarges sample loading and trapping efficiency, thus bypasses the tradeoff between sample capacity and downstream detection sensitivity. This integrated approach, formed by synergistic utilization among electric field, membrane, and fluidic handling at the microscale, reduces the overall complexity of crude samples in one step for direct MS analysis. The sample preparation goals, including enrichment, desalting, removal of noncharged contaminants, and initial fractionation, can be rapidly performed in a single device. The strategy facilitates reproducible MS quantification by circumventing traditional laborious and time-consuming sample preparation steps. In addition, MEPD extended the ion trap linear dynamic range from 2 to at least 4 orders of magnitude by eliminating ion suppression effect, enriching target analyte(s), and decreasing sample loss during integrated sample preparation.