Anion-Induced Uniform and Robust Cathode-Electrolyte Interphase for Layered Metal Oxide Cathodes of Sodium Ion Batteries.

Layer metal oxides demonstrate great commercial application potential in sodium-ion batteries, while their commercialization is extremely hampered by the unsatisfactory cycling performance caused by the irreversible phase transition and interfacial side reaction. Herein, trimethoxymethylsilane (TMSI) is introduced into electrolytes to construct an advanced cathode/electrolyte interphase by tuning the solvation structure of anions. It is found that due to the stronger interaction between ClO4- and TMSI than that of ClO4- and PC/FEC, the ClO4--TMSI complexes tend to accumulate on the surface of the cathode during the charging process, leading to the formation of a stable cathode/electrolyte interface (CEI). In addition, the Si species with excellent electronic insulation ability are distributed in the TMSI-derived CEI film, which is conducive to inhibiting the continuous side reaction of solvents and the growth of the CEI film. As a result, under a current density of 250 mA g-1, the capacity retention of the NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode after 200 cycles in the TMSI-modified electrolyte is 74.4% in comparison to 51.5% of the bare electrolyte (1 M NaClO4/PC/5% FEC). Moreover, the NFM cathode shows better kinetics, with the specific discharge capacity increasing from 22 to 67 mAh g-1 at 300 mA g-1. It also demonstrates greatly improved rate capability, cycling stability, and Coulombic efficiency under various operating conditions, including high temperature (55 °C) and high cutoff voltage (2.0-4.3 V vs Na+/Na).

Significantly Improving the Initial Coulombic Efficiency of TiO2 Anode for Sodium-Ion Batteries.

Titanium dioxide (TiO2) can serve as a candidate anode material for sodium-ion batteries (SIBs) with the merits of their low cost, abundance, and environment friendliness. However, its low initial Coulombic efficiency (ICE) and sluggish sodium-ion diffusion greatly limit its further practical applications. Herein, we report a one-step prepotassiation strategy to modify commercial TiO2 by a spontaneous chemical reaction using potassium naphthalene (K-Nt). Prepotassiation effectively compensates for the irreversible Na loss and induces a homogeneous, dense, and robust artificial solid electrolyte interphase (SEI) on its surface. The well-distributed artificial SEI suppresses the excessive electrolyte decomposition, contributing to rapid interfacial kinetics and stable Na+ insertion/extraction. Therefore, such modified commercial TiO2 anodes demonstrate significantly improved ICE (72.4%) and outstanding rate performance (176.4 mAh g-1 at 5 A g-1). This simple and efficient method for promoting ICEs and interfacial chemistry also demonstrates universality and practical value for other anodes in SIBs.

Spatiotemporal heterogeneity and decoupling decomposition of industrial carbon emissions in the Yangtze River Delta urban agglomeration of China.

The objective of this study is to identify the spatiotemporal change law and the leading factors of industrial carbon emission decoupling. Based on the industrial carbon emission level of the Yangtze River Delta urban agglomeration (YRDUA) from 2006 to 2020, the spatiotemporal heterogeneity was explored with the help of the spatial Markov chain, the Tapio decoupling model was used to analyze its decoupling state from the industrial economy, and its driving factors were decomposed using the Kaya identity and logarithmic mean Divisia index (LMDI) model. The results show that (1) in 51.9% of the YRDUA's cities, the industrial carbon emission situation was stable, the emission reduction observation area (medium carbon) occupied a dominant position, and the emission reduction key area (relatively high carbon) gradually decreased. (2) Industrial carbon emissions had spatial overflow and path dependency characteristics, and the probability of carbon emission type transfer maintaining the original state reached 80.0%. From 2006 to 2011, the average probability of the downward migration of high-carbon cities was 5.0%. From 2011 to 2020, the average probability of the upward transfer of low-carbon cities was 9.4%. (3) The negative decoupling rate of carbon emissions in the YRDUA experienced a transition from 3.7% to 44.4% and then back to 7.4%, showing spatial imbalance. Unsatisfactory decoupling cities were concentrated along the Yangtze River and in coastal areas. (4) The promoting efficiency of energy intensity, carbon emission coefficient, and employment structure was gradually strengthened, and the carbon-increasing effect of labor input was gradually weakened. (5) The decoupling mode of heavy difficult cities is dominated by the three-factor balanced type, which is jointly affected by industrial production, labor input, and carbon emission coefficient. The findings in this study can provide inspiration for industrial carbon emission reduction in megalopolises.

Spatiotemporal pattern of regional carbon emissions and its influencing factors in the Yangtze River Delta urban agglomeration of China.

Urbanization is a critical factor affecting regional carbon emissions. Clarifying the linkage between urbanization and carbon emissions can provide a decision-making reference to realize China's goal of carbon neutrality. This article examines the spatiotemporal patterns of urbanization and carbon emissions in the Yangtze River Delta urban agglomeration from 2008 to 2018. A complete set of variables is considered to construct relevant land and ecological urbanization variables, and the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model and spatial Durbin model (SDM) are adopted to explore the impact of various driving factors on carbon emissions. The results indicate that (1) during the study period, the carbon emissions in the Yangtze River Delta urban agglomeration exhibited a fluctuating increase and that the incremental carbon emissions followed a downward trend. (2) Carbon emissions exhibited a positive spatial correlation. Cold- and hotspot areas indicated a three-gradient pattern from west to east, and a concentric circle radiation pattern occurred with Shanghai as the core. Carbon emissions were spatially imbalanced, but the centre of gravity slightly fluctuated, with a total migration distance of 38.48 km, indicating a migration trend towards the southeast. (3) Regarding the two considered dimensions of urbanization, all driving factors except urbanization played a role in carbon emission enhancement. Consequently, for every 1% increase in economic factors, the carbon emissions correspondingly increased by 0.43-0.57%. Hence, economic factors are the most important factors promoting increased carbon emissions. In the ecological urbanization dimension, urbanization caused a non-significant decrease in carbon emissions, while there was no spillover effect on carbon emissions in neighbouring areas. Accordingly, carbon emission reduction efforts should promote the transformation of urbanization from a land-driven process to an ecologically driven process and realize the synergies among carbon emission reductions, urban development, and land use.

Spatial spillover effects of urbanization on carbon emissions in the Yangtze River Delta urban agglomeration, China.

To achieve a win-win situation for both urbanization and carbon emissions reduction from a spatiotemporal perspective, we need to identify the salient links between urbanization and carbon emissions in different dimensions. Using 2008-2018 panel data on the Yangtze River Delta urban agglomeration, this paper constructs a Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model based on four dimensions of urbanization: population, economy, land, and ecology. Additionally, it uses a whole group of variables for reference, constructs a Spatial Durbin model (SDM) to estimate the spatial effect, and empirically investigates the spatial dependence of carbon emissions and the influence of various driving factors. The results show that (1) in the temporal dimension, the historical carbon emissions of the study area continue to increase. However, the extent to which they are doing so is slowing, the number of low carbon emissions areas has significantly decreased, the number of medium carbon emissions areas have significantly increased, the number of high and relatively high carbon emissions areas are relatively stable, and energy intensity continues to decline. (2) In the spatial dimension, Shanghai, Suzhou, and their surrounding cities have always been carbon emissions hotspots, high and relatively high carbon emissions areas are mainly concentrated in these cities. Low carbon emissions areas and cold spots are mainly distributed in Anhui Province. Medium carbon emissions areas show a great spatial and temporal evolution and are distributed in all provinces. (3) In the four dimensions of urbanization, per capita GDP will not only affect regional carbon emissions but also have a spatial spillover effect. For every 1% increase in the economic factors, carbon emissions in neighboring regions will increase by 0.38-0.43%. Population, economic, and technological factors have significant positive effects on carbon emissions, and economic factor is the most important factor. (4) In different dimensions of urbanization, there are obvious heterogeneities in the impacts of different factors on carbon emissions. Among them, the elasticity coefficient of per capita GDP and energy intensity is the smallest among the dimension of land urbanization, and the elasticity coefficient of the total population is the smallest among the dimension of population urbanization. Therefore, when formulating carbon emissions reduction policies, it is necessary to fully consider the spatial spillover effects, determine the optimal population size threshold, advocate for a low-carbon lifestyle, promote clean technology, and realize information exchange and policy interaction across regions from the perspective of holistic governance.

Determination of ultra-trace levels of titanium in human serum using inductively coupled plasma tandem mass spectrometry based on O2/H2 reaction gas.

This study proposes a new strategy to determine ultra-trace Ti in human serum using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The human serum samples were diluted with 1% (v/v) HNO3, followed by the determination of ultra-trace Ti using ICP-MS/MS. In the MS/MS mode, a small amount of H2 was mixed with O2 (the reaction gas) in a collision reaction cell (CRC) to form an O2/H2 reaction mixture, and then, the conversion of Ti+ to TiO+ was determined by the O2 mass shift method. High concentrations of Ca, S, and P in human serum were ionized in plasma, and the formed Ca+, SO+, and PO + reacted with O2 in CRC to form CaO+, SO2+, and PO2+ to interfere with the determination of TiO+. We employed the mass shift reaction of H2 and oxide ions to eliminate this interference. This method was evaluated using the human serum sample spike recovery experiment and comparative analysis by sector field (SF)-ICP-MS. The results showed that using reaction gas mixture O2/H2 reduced the background equivalent concentration (BEC) of Ti and improved sensitivity. The values determined by this method were consistent with the SF-ICP-MS values, which confirmed its accuracy and reliability. The limit of detection (LOD) of Ti was 0.78-7.20 ng L-1, the recovery was 96.0%-104%, and the relative standard deviation (RSD) was 2.0%-4.2%. This method has solved the problem that the determination of ultra-trace Ti in human serum cannot be accurately determined using O2 reaction mode. It realizes the interference-free and highly sensitive determination of the ultra-trace Ti in samples with high levels of Ca, S, and P and provides a new technique for high-throughput and accurate determination of ultra-trace Ti in human serum.

Determination of the Non-metallic Elements in Herbal Tea by Inductively Coupled Plasma Tandem Mass Spectrometry.

The feasibility of using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) to overcome spectral overlaps in the determination of non-metallic elements was investigated. The contents of Si, P, S, Cl, Br, and I in herbal tea were determined by using ICP-MS/MS after microwave digestion. In the MS/MS mode, O2 and H2 were consecutively used as reaction gases. Low background equivalent concentration (BEC) and limit of detection (LOD) of analytes were obtained when using O2 mass shift, H2 mass shift, and H2 on-mass methods. The LODs for Si, P, S, Cl, Br, and I were 0.41, 0.048, 0.34, 0.76, 0.055, and 0.007 µg L-1, respectively. Standard reference materials NIST SRM 1515 (apple leaves) and NIST SRM 1547 (peach leaves) were used to evaluate the accuracy of the analytical method. The developed method was used to analyze 20 herbal teas. The ranges of values for Si, P, S, Cl, Br, and I in herbal tea were 236-4100, 1830-4360, 1290-3850, 335-4620, 0.86-8.21, and 0.091-0.65 µg g-1, respectively. The results showed that several non-metallic elements essential for the human body might be obtained by drinking herbal tea.

Assessing Changes in Ecosystem Service Values in Response to Land Cover Dynamics in Jiangxi Province, China.

This paper examines the ecosystem service values of Jiangxi province, China using the benefit transfer approach. The land cover dynamics results show that cropland and forest are the main land cover types in Jiangxi province. Urban land drastically increased after 2000, expanding from 846.54 km2 in 2000 to 2317.48 km2 in 2015. Forest and water obviously decreased across the study periods. Consequently, the total ecosystem service values decreased from 37.91 × 1010 Yuan in 1995 to 35.27 × 1010 Yuan in 2015. The values showed a declining trend, especially during the 1995-2000 period. The largest declines in ecosystem service values were caused by decreases in forest and water cover. Regulating services experienced the largest declines in ecosystem services value. Moreover, water supply showed the largest decline in ecosystem service value between 1995 and 2015. Not surprisingly, food production increased in the whole period, especially in the 1995-2000 period. Forest and cropland played the most important roles in the total ecosystem service values of Jiangxi province. We then discussed the relationship among ecosystem services based on the ecosystem service trade-off degree. The results show that the dominant relationship among ecosystem services in Jiangxi province was synergy; thus synergy mostly occurred in all ecosystem services except for food production from 1995 to 2015. However, during the 1995-2000 period, trade-offs mainly existed in both food production and waste treatment. The proportion of synergy greatly increased in the 2000-2015 period, and the synergistic relationship between waste treatment and other ecosystem services increased. However, the trade-off relationship between food production and other ecosystem services still has not improved, which should be concerned in the future. Changes in the percentage share of cropland showed a declining trend; thus, the potential risk of cropland loss should be monitored.

Rapid determination of trace elements in serum of hepatocellular carcinoma patients by inductively coupled plasma tandem mass spectrometry.

The occurrence and development of hepatocellular carcinoma (HCC) is related to the level of trace elements. The mechanism of changes in trace element concentration and the identification of HCC risks associated with them are not clear. Therefore, an accurate and reliable approach for quantification of the level of trace elements in the serum of liver cancer patients is of great significance. In this study, we proposed a novel strategy for accurate determination of trace elements such as Mn, Fe, Ni, Cu, Zn, and Se in the serum of HCC patients based on inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). In the MS/MS mode, N2O was used as the reaction gas, and an octopole reaction system (ORS) was employed to provide interference-free conditions and a sufficiently low limit of detection (LOD) for the determination of analytical elements. The internal standard elements with similar masses and similar mass spectrometry behavior were selected to correct the matrix effect. The LODs of Mn, Fe, Ni, Cu, Zn, and Se were as low as 0.013, 0.25, 0.010, 0.020, 0.17, and 0.008 µg L-1, respectively. Bovine serum (SRM 1598a) was adopted as the standard reference material to evaluate the accuracy of the method, and the developed method was successfully applied to determine the content of Mn, Fe, Cu, Zn, Ni, Se in serum from HCC patients. The obtained results were in agreement with that of sector field ICP-MS (SF-ICP-MS). The contents of Fe and Cu in the serum of HCC patients were higher compared to that of healthy controls, while the contents of Zn and Se were lower than that of healthy controls. Furthermore, no significant differences were observed in the contents of Mn and Ni in the serum of HCC patients and healthy controls.

Rapid identification of Lilium species and polysaccharide contents based on near infrared spectroscopy and weighted partial least square method.

Polysaccharide is the main active compound of Lilium, and showed many activities, such as hypoglycemic, antioxidant, immune-modulatory. There are three types' Lilium in China market, i.e. Lilium lancifolium Thunb (JD), Lilium davidiivar. Unicolor Salisb (L. davidii var)(LZBH), and Lilium brownii F.E. Brown var. viridulum Baker (BH). Near infrared spectroscopy (NIR) technique has become popular in the fields of quality control, due to its advantages, such as fast, non-destructive, and can detect several ingredients, simultaneously. In this study, a classification model was established based on NIR technique and random forest method to accurately distinguish three types' Lilium species, and the classification accuracy reached 94.37%. Furthermore, taking the effects of neighbor wavelength into account, a new weighted partial least square algorithm was proposed to establish an accurate and quantitative model for predicting the polysaccharide contents of these samples. In the model establishing process, some signal pre-treatment methods were optimized, and the validation results with highest determination coefficient (R2) and low root mean square errors of prediction (RMSEP) were, 0.9455 and 0.9098, respectively. The obtained results showed that combined NIR technique with chemometrics was an effective and green method for quality control.

Warning of negative effects of land-use changes on ecological security based on GIS.

Urbanization leads to dramatic changes in regional land-use patterns and threatens regional ecological security. Based on GIS and existing key ecological spaces, timely threat warnings to regional ecological spaces caused by artificial land-use changes and the identification of appropriate precautionary measures are necessary for the sustainable development of regional land resources. Taking 2010 as the base year, the study forecasts the demand for new construction land in the surveyed region in 2015 and 2030 using a Markov model; on this basis, a logistic cellular automata (CA) model is built to forecast the land use distribution related to construction land expansion and requisition-compensationbalanceofcultivated land. An OA value of 85.05% and a Kappa coefficient of 77.48% indicate a good simulation accuracy. By overlaying the existing regional key ecological spaces with the forecasted distribution of land-use changes, potential ecological security alerts are derived from the regional land-use changes. Results show that according to the current development mode, by 2030, the regional ecological security in the study area will be threatened by 35% of the new construction land and 80% of the supplementary cultivated land. The early warning mechanism for land-use ecological security can effectively forewarn the ecological threats derived from land use, thus helping decision makers to prevent risks in advance. Finally, the corresponding precautionary strategy is put forward.

Effect of the grain-growing purpose and farm size on the ability of stable land property rights to encourage farmers to apply organic fertilizers.

The application of organic fertilizer by farmers is an important method for promoting the transition of agricultural production from increasing the yield to improving the quality and safety of agricultural products and realizing the green development of agriculture. The behavior of farmers can have a direct impact on organic fertilizer application, and the active participation of farmers can effectively reduce moral hazards and improve governance efficiency. A consensus appears to have been reached regarding the importance of land property rights stability (LPRS) for farmers' organic fertilizer application (FOFA) in China; however, few studies have focused on the conditions under which LPRS exerts an effect or the extent of the effect. Moreover, the grain-growing purpose and farm size are rarely included as driving factors underlying the impact of LPRS on FOFA; thus, biased estimations are easily formed. This study analyzed the influence mechanism of LPRS on FOFA and its dependent conditions using the 2017 China Rural Household Panel Survey from Zhejiang University and conducted an empirical analysis via a logit model. The results showed that LPRS could enable farmers to apply organic fertilizer, although the degree of its impact will vary due to differences in the grain-growing purpose and farm size. Currently, selling products is not conducive to the application of organic fertilizer and will reduce the positive impact of LPRS on the application of organic fertilizer by farmers, whereas expanding the farm size will enhance the positive impact of LPRS. The government should constantly improve the methods and channels for realizing high-quality and high-priced agricultural products and fully acknowledge the role of market demand in guiding farmers' agricultural production, which will increase their enthusiasm for organic fertilizer application. The government should also improve the contract management system for land transfer to strengthen the ability of farmers to expand their farm size to fully demonstrate the role of large-scale farmers.

Bibliometric analysis of highly cited articles on ecosystem services.

This paper presents global research trends involving highly cited articles on ecosystem services from 1981 to 2017 based on a bibliometric analysis of such articles from the SCI-E and SSCI databases of the Web of Science. The analysis revealed that there were 132 highly cited articles, most of which were published between 2005 and 2014. Based on author keywords, the term ecosystem services was strongly linked to biodiversity. The top three journals in terms of total number of highly cited articles published were Ecological Economics, PNAS, and Ecological Indicators. Despite ranking sixth overall, Science ranked first in both impact factor and total citations per article. The US, UK, Netherlands, Spain, and Sweden were the top five most productive and cooperative countries in the world based on total number of highly cited articles and co-authorship network, respectively. The US was highly connected to Canada, the Netherlands, China and the UK. Stockholm University and Stanford University were the most productive institutions in Europe and North America, respectively. Stanford University is associated with many scholars in the field of ecosystem services research because of the InVEST model. Robert Costanza was the most prolific and highly cited author, the latter being largely due to the first valuation of the world's ecosystem services and natural capital, he and his co-authors published in 1997 in Nature. Terrestrial, urban, and forest ecosystems were the top types of ecosystems assessed. Regulating and provisioning services were the major ecosystem services studied. Quantitative and qualitative assessments were the main research focus. Most of these highly cited studies on ecosystem services are done on areas geographically located in North America and Europe.

Application of near infrared spectroscopy for rapid determination the geographical regions and polysaccharides contents of Lentinula edodes.

In this study, a calibration model based on Near-infrared spectroscopy (NIR) technique and chemometrics method was developed for rapid and non-destructive detecting the polysaccharide contents of lentinula edodes samples collected from different regions. The polysaccharide contents of these samples were firstly determined by standard phenol-sulphruic acid method. Then, NIR spectra of these samples were collected by using Fourier transform infrared spectrometry. Based on these experimental data, a random forest method was further used to distinguish the regions of these samples, with a classification accuracy of 96.6%. After that, a rapid, accurate, and quantitative model was established for predicting the polysaccharide contents of these samples. In the model establishing process, some signal pre-treatment methods were optimized, and the validation results with highest determination coefficient (R2) and low root mean square errors of prediction (RMSEP) were, 0.925 and 0.720, respectively. These results showed that combined NIR technique with chemometrics was an effective and green method for lentinula edodes quality control.

An Improved Weighted Partial Least Squares Method Coupled with Near Infrared Spectroscopy for Rapid Determination of Multiple Components and Anti-Oxidant Activity of Pu-Erh Tea.

Background: Pu-erh tea is a unique microbially fermented tea, which distinctive chemical constituents and activities are worthy of systematic study. Near infrared spectroscopy (NIR) coupled with suitable chemometrics approaches can rapidly and accurately quantitatively analyze multiple compounds in samples. Methods: In this study, an improved weighted partial least squares (PLS) algorithm combined with near infrared spectroscopy (NIR) was used to construct a fast calibration model for determining four main components, i.e., tea polyphenols, tea polysaccharide, total flavonoids, theanine content, and further determine the total antioxidant capacity of pu-erh tea. Results: The final correlation coefficients R square for tea polyphenols, tea polysaccharide, total flavonoids content, theanine content, and total antioxidant capacity were 0.8288, 0.8403, 0.8415, 0.8537 and 0.8682, respectively. Conclusions: The current study provided a comprehensive study of four main ingredients and activity of pu-erh tea, and demonstrated that NIR spectroscopy technology coupled with multivariate calibration analysis could be successfully applied to pu-erh tea quality assessment.

Multielement analysis of Zanthoxylum bungeanum Maxim. essential oil using ICP-MS/MS.

The concentrations of trace elements (Cr, Ni, As, Cd, Hg, and Pb) in Zanthoxylum bungeanum Maxim. essential oil (ZBMEO) were determined by inductively coupled plasma tandem mass spectrometry. The ZBMEO sample was directly analyzed after simple dilution with n-hexane. Aiming for a relatively high vapor pressure of n-hexane and its resultant loading on plasma, we used a narrow injector torch and optimized plasma radio frequency power and carrier gas flow to ensure stable operation of the plasma. An optional gas flow of 20% O2 in Ar was added to the carrier gas to prevent the incomplete combustion of highly concentrated organic carbon in plasma and the deposition of carbon on the sampling and skimmer cone orifices. In tandem mass spectrometry mode, O2 was added to the collision/reaction cell to eliminate the interferences. The limits of detection for Cr, Ni, As, Cd, Hg, and Pb were 2.26, 1.64, 2.02, 1.35, 1.76, and 0.97 ng L-1, respectively. After determination of 23 ZBMEO samples from different regions in China, we found that the average concentration ranges of trace elements in the 23 ZBMEO samples were 0.72-6.02 ng g-1, 0.09-2.87 ng g-1, 0.21-5.84 ng g-1, 0.16-2.15 ng g-1, 0.13-0.92 ng g-1, and 0.17-0.73 ng g-1 for Cr, Ni, As, Cd, Hg, and Pb, respectively. The trace elements in ZBMEO differed significantly when different extraction technologies were used. The study revealed that the contents of the toxic elements As, Cd, Hg, and Pb were extremely low, and hence they are unlikely to pose a health risk following ZBMEO ingestion. Graphical abstract The working mechanism of sample analysis by ICP-MS/MS.

Impact of changes in labor resources and transfers of land use rights on agricultural non-point source pollution in Jiangsu Province, China.

This study systematically explores the likely mechanisms driving the effect of the transfer of agricultural land use rights (ALURs) on agricultural non-point source pollution (ANSP) in the context of changing agricultural labor resources. It quantitatively estimates the direction and degree of this influence from a microeconomic perspective using data from rural households. The results reveal that economies of scale caused by ALURs transfers contribute to reducing both the ANSP and marginal costs of inputs. Changes in agricultural labor resources lead to reductions in agricultural labor supply and negatively impact on ANSP. Encouraging farmers to participate in ALURs transfers, therefore, helps to reduce ANSP. The government and related departments should implement policies that support farmers who decide to rent an entire village's land or the adjacent land to achieve economies of scale. Accelerating the development of small farm machinery that is suitable for smaller farm plots and the elderly can serve to reduce the use of chemical fertilizer and promote green production and sustainable agricultural development.

[Determination of Impurity Elements in Rosin with Inductively Coupled Plasma Mass Spectrometry].

An analytical method for the content determining of impurity elements in rosin was established. After being dissolved and diluted in ethanol, the rosin was analyzed directly with inductively coupled plasma mass spectrometry (ICP-MS). Some experiment conditions were optimized, such as the RF power, carrier gas flow, sample amount, and increase the temperature of plasma center channel, to improve the ionization efficiency. Proper oxygen concentration was added in plasma to make sure organic carbon been complete burned, resulting in carbon deposits eliminate and signal stable. Though equipment turn and isotopes selection can effectively eliminate interferences caused by oxide and doubly charged ions mass spectrums. A large amount of isobars and polyatomic ion interference were avoided. The collision reaction cell (CRC) technology was used to further eliminate the mass spectra interference, with He collision model and H2 reaction model, respectively. The results showed that detection limits of different impurity elements were within the range from 0.002 to 0.035 µg·g-1, and the recoveries of real added sample were between the range from 94.00% to 106.00%, and relative standard deviation is less than 3.34%. This method enables to detect rosin dissolved in ethanol directly and needs no special sample preparation equipment. This simple, fast and accurate approach provides us a new analysis method for the quality valuation of impurity elements in rosin.

[Study on the Detection of Trace Sulphur in Diesel with Inductively Coupled Plasma Optical Emission Spectroscopy].

The method to detect trace sulphur content in diesel with inductively coupled plasma optical emission spectrometry (ICP-OES) was established. Kerosene sample was directly diluted, and then trace sulphur content in the solution was analyzed directly with ICP-OES. High concentrations of organic solvents with high saturation vapor pressure can cause the increasing of the loading of plasma, which would interfere the determination. In order to keep the working stability of equipment, operating parameters, such as RF power, loading gas velocity, were being optimized. First, the axially-viewed technology was adopted to increase the sensitivity of determination. Second, the analysis spectral lines of sulfur are located in ultraviolet area; therefore the Ar was adopted as protective air, and increase Ar clean time to keep the pure of sight source. Third, the condensation and deposition of high concentrations of carbon could be avoided effectively by introducing O2 to plasma. Some detailed processes were used to further keep the stability of determinate signals such as: using element Y as internal standard to correct matrix effectives and compensate the errors caused by the spectral line shift, some automatic software were used to correct signal background. The results showed that the detection limits was 0.2 µg·L-1, the relative standard deviation (RSD) was in range of 1.6%~2.1%, and the recovery of the methods was in range of 97.4%~101.8%. The method has the following advantages: simple sample pretreatment, fast analyzing speed, low detection limitation, high precision and accuracy, as well as wide linear dynamic range. It can be used for rapid analysis of trace sulfur in diesel.

[Direct Determination of Heavy Metal Elements in Propolis by Inductively Coupled Plasma Mass Spectrometry].

In current study, a method was established for simultaneous quantitative analysis of Cr, Ni, As, Cd, Sb, Sn, Hg and Pb in propolis by using inductively coupled plasma mass spectrometry. Before analyzed by ICP-MS, the propolis was diluted with n-propanol/xylene (70 : 30, φ). Organic sample can remain stable by diluting with n-propanol/xylene, result from long-time sample dispersion in the solution. Carbon accumulation on the sampling cone, which comes from the high carbon content of butter, will clog the orifice and decrease analysis sensitivity. Thus a small amount of oxygen was added into the argon gas line to eliminate carbon. ORS was used to eliminate the polyatomic interferences caused by the high salty matrixes. The effects of the He collision gas flow rate on estimating detection limits of Cr, Ni and As were investigated. The matrix effects and the instrument drift have been calibrated with Rh as internal standard element. The results show that the detection limits is in the range of 20.8-102.7 ng x L(-1), the recovery is in the range of 92.0%-109.0%, and the RSD is less than 3.5%. This method was simple, sensitive and precise to simultaneously analyze 8 heavy metal elements in propolis.