Cadmium-Assisted Photochemical Vapor Generation of Arsenic from Low Concentration of Formic Acid Media.

A highly sensitive method for the determination of total arsenic (As) has been developed using photochemical vapor generation (PVG) coupled with inductively coupled plasma mass spectrometry (ICP MS). The efficient PVG of As is reported for the first time in the presence of Cd(II) in diluted formic acid (FA) medium. The PVG efficiency of 93 ± 1% can be achieved in the system with 0.

Origin, formation, and transformation of different forms of silica in Xuanwei Formation coal, China, and its' emerging environmental problem.

The study on the origin of quartz and silica in Xuanwei Formation coal in Northwest Yunnan, China, is helpful to understand the relationship between quartz and silica and the high incidence of lung cancer from the root. To address these questions, the mineralogy and microscopic studies of silica in Xuanwei Formation coal were performed. The following results were obtained: (1) silica in the late Permian Xuanwei Formation coal seams originated from detrital input, early diagenesis, and late diagenesis.

Research of nuclide identification method based on background comparison method.

Radioactive material inspection in public is important to nuclear safety, and it is also the key security for holding large-scale events, while fast and efficient means of detecting radioactive materials are an important technical guarantee for nuclear safety. In this paper, energy and time distribution characteristics information of the natural background and target nuclide gamma particles are used to improve the sequential background comparison method. By using those energy and time distribution characteristics information, with the half-life and characteristic gamma-ray energy and branching ratio information of the nuclide, the response time and the identification accuracy of extremely low radioactive nuclides detected under natural-radiation background can be improved.

Ecological Health Risk Assessment and Source Identification of Heavy Metals in Surface Soil Based on a High Geochemical Background: A Case Study in Southwest China.

A total of 28,095 surface soil samples were collected in areas with high natural background levels; the potential ecological risk is generally low, and the high-risk area is small and mainly affected by lead−zinc mines. The contribution to the potential ecological risk factor (RI) is as follows: Hg > Cd > As > Pb > Cu > Ni > Cr > Zn, with noncarcinogenic chronic risks of Cr > As > Cd > Pb > Ni > Cu > Hg > Zn; furthermore, dermal contact is the main pathway of exposure causing health risks. The total carcinogenic risks caused by heavy metals were as follows: Cr > Cd > As > Pb; and the risks posed by Cr, Cd, and As were higher than the threshold value (1.

[Geochemical Characteristics and Source Apportionment of Soil Elements in an Urban-rural Integration Area: A Case Study in the Qinglong Area of Tianfu New District].

The Qinglong Area of Tianfu New District in China is the connection area of Chengdu city, Sichuan Province, which dominantly supports the primary agricultural products for the metropolis. The soil quality, therefore, has been deteriorating in recent decades due to the intensive planting and industrial pollution. Thus, the evaluation of soil quality and the identification of the pollution sources are significant for sustainable soil planting and regulation.

Impact of Gas-Liquid Interface on Photochemical Vapor Generation.

Interfacial effect has attracted increasing interest as the inherent asymmetric environment of a gas-liquid interface leads to different chemical and physical properties between this region and the bulk phase, resulting in enhanced chemical processes, specific reactions, and mass transfer at the interface. Photochemical vapor generation (PVG) is regarded as a simple and green sample introduction method in atomic spectrometry. However, the photochemical behavior of elements with the interface is not known.

Sources of seasonal wetland methane emissions in permafrost regions of the Qinghai-Tibet Plateau.

In this study, systematic soil methane cycle geochemical monitoring was carried out in a typical gas hydrate region in the Qinghai-Tibet Plateau. Soil gas samples were collected for hydrocarbon components and carbon isotope analysis. Meanwhile, soil-methane fluxes from the upper active layer (20-30 cm) were monitored during six months of one year.

Design and Verification of Humidity Sensors Based on Magnesium Oxide Micro-Arc Oxidation Film Layers.

Humidity detection range is an important indicator for measuring the performance of humidity sensors, but semiconductor humidity sensors often face the problems of narrow detection ranges and insufficient detection sensitivities. In this paper, a magnesium oxide (MgO) humidity sensor based on micro-arc oxidation (MAO) technology was designed to solve these problems by simultaneously using impedance and capacitance as the response signals, as well as by normalizing the output of the two signals. The experimental results showed that the average output of the micro-arc MgO ceramic film, with impedance as the response signal, could reach 150 in the low relative humidity(RH) range (11.

Reduction of Interferences Using Fe-Containing Metal-Organic Frameworks for Matrix Separation and Enhanced Photochemical Vapor Generation of Trace Bismuth.

Photochemical vapor generation (PVG) has emerged as a promising sample introduction method for atomic spectrometry in recent years. Despite its great success, a major impediment for the wide application of PVG is the interferences from the coexisting ions, especially transition-metal ions. In this work, iron and 1,3,5-benzenetricarboxylic (Fe-BTC), a Fe-containing metal-organic framework (MOF) material, was synthesized and first used as a platform integrating the sample matrix separation, preconcentration, and photocatalysis for the highly selective determination of elements by PVG.

Enhanced Photochemical Vapor Generation for the Determination of Bismuth by Inductively Coupled Plasma Mass Spectrometry.

An enhanced photochemical vapor generation (PVG) sample introduction procedure is developed for the determination of trace Bi with inductively coupled plasma mass spectrometry (ICP MS) by the addition of iron. Gas chromatography mass spectrometry (GC-MS) reveals that (CH)Bi is the major component of the volatile Bi species formed in the presence of 20% (v/v) acetic acid, 5% (v/v) formic acid, and 60 μg mL Fe under UV irradiation. The addition of Fe not only largely increases the PVG efficiency of Bi but also accelerates the reaction kinetics of photochemical reduction of Bi.

Photochemical Vapor Generation of Tellurium: Synergistic Effect from Ferric Ion and Nano-TiO.

Photochemical vapor generation (PVG) is emerging as a promising analytical tool for Te determination, thanks to its efficient matrix separation, and simple and green procedure. However, the low PVG generation efficiency of Te is the bottleneck for its wide application in environmental samples containing trace Te. Herein, we reported a high efficient PVG for Te determination by synergistic effect of ferric ion and nano-TiO.

Environmental water chemistry and possible correlation with Kaschin-Beck Disease (KBD) in northwestern Sichuan, China.

During the past several decades, etiological and geochemical studies tend to link the Kaschin-Beck Disease (KBD) to the deficiency of some specific trace elements (e.g., selenium and iodine) in the environment; however the link has been proven inconclusive.

Characteristics, Sources and Health Risk Assessment of Trace Metals in PM in Panzhihua, China.

Ambient PM air samples were collected at two industrial sites and one urban residential site in the mining city of Panzhihua, China, from April, 2014, to January, 2015. Mass concentrations of ten trace metals (As, Cd, Cr, Ni, Co, V, Mn, Cu, Pb, and Zn) in PM were determined by inductively coupled plasma-mass spectrometry. The results showed Zn, Pb, Cu, Mn and V were the most abundant elements from the industrial sites.

The spatial relationship between human activities and C, N, P, S in soil based on landscape geochemical interpretation.

The development and formation of chemical elements in soil are affected not only by parent material, climate, biology, and topology factors, but also by human activities. As the main elements supporting life on earth system, the C, N, P, S cycles in soil have been altered by human activity through land-use change, agricultural intensification, and use of fossil fuels. The present study attempts to analyze whether and how a connection can be made between macroscopical control and microcosmic analysis, to estimate the impacts of human activities on C, N, P, S elements in soil, and to determine a way to describe the spatial relationship between C, N, P, S in soil and human activities, by means of landscape geochemical theories and methods.

Metal ion-assisted photochemical vapor generation for the determination of lead in environmental samples by multicollector-ICPMS.

A novel and sensitive approach for the accurate and precise determination of Pb in environmental samples is presented using transition metal ion-assisted photochemical vapor generation (PVG) for sample introduction with multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) detection. A significant improvement in PVG efficiency of lead is achieved in the presence of transition metal ions (Co(2+) and Ni(2+)) in solutions of 5% (v/v) formic acid. The determination of Pb in digests of sediment or soil samples is readily achieved due to coexisting transition metal ions which facilitate the PVG reaction.

Direct determination of mercury in cosmetic samples by isotope dilution inductively coupled plasma mass spectrometry after dissolution with formic acid.

A new method was proposed for the accurate determination of mercury in cosmetic samples based on isotopic dilution (ID)-photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometry (ICP MS) measurement. Cosmetic samples were directly dissolved in formic acid solution and subsequently subjected to PVG for the reduction of mercury into vapor species following by ICP MS detection. Therefore, the risks of analyte contamination and loss were avoided.

Determination of total mercury in biological tissue by isotope dilution ICPMS after UV photochemical vapor generation.

A method is developed for the determination of trace mercury in biological samples using photo chemical vapor generation (PVG) and isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS) detection. Biological tissues were solubilized in formic acid. Subsequently, the sample solutions were exposed to an ultraviolet (UV) source for the reduction of mercury into vapor species prior to ICPMS measurements.

[The study of baseline estimated in digital XRF analyzer].

For the digital X-ray fluorescence analyzer, the voltage of the instability baseline will directly affect the performance of the instrument, resulting in decreased energy resolution. In order to solve this problem, Kalman filtering algorithm was used for pulse signal baseline estimate in the digital X-ray fluorescence. Whether using the classic Kalman filter, or the simplified sage-husa, or the improved sage-husa, their baseline filtering effects were all poor.

Meta-analysis of the relation between the VDR gene TaqIpolymorphism and genetic susceptibility to prostate cancer in Asian populations.

Background: Polymorphisms of the Taq I gene have been associated with prostate cancer risk.

Methods: We applied a fixed-effects model to combine odds ratios (ORs) and 95% confidence intervals (95% CI). The Egger's test was carried out to evaluate potential publication bias.