Optimization of microwave‐assisted extraction for six inorganic and organic arsenic species in chicken tissues using response surface methodology

Response surface methodology was applied to optimize the parameters for microwave‐assisted extraction of six major inorganic and organic arsenic species (As(III), As(V), dimethyl arsenic acid, monomethyl arsenic acid, p‐arsanilic acid, and roxarsone) from chicken tissues, followed by detection using a high‐performance liquid chromatography with inductively coupled mass spectrometry detection method, which allows the simultaneous analysis of both inorganic and organic arsenic species in the extract in a single run. Effects of extraction medium, solution pH, liquid‐to‐solid ratio, and the temperature and time of microwave‐assisted extraction on the extraction of the targeted arsenic species were studied. The optimum microwave‐assisted extraction conditions were: 100 mg of chicken tissue, extracted by 5 mL of 22% v/v methanol, 90 mmol/L (NH₄)₂HPO₄, and 0.07% v/v trifluoroacetic acid (with pH adjusted to 10.0 by ammonium hydroxide solution), ramping for 10 min to 71°C, and holding for 11 min. The method has good extraction performance for total arsenic in the spiked and nonspiked chicken tissues (104.0 ± 13.8% and 91.6 ± 7.8%, respectively), except for the ones with arsenic contents close to the quantitation limits. Limits of quantitation (S/N = 10) for As(III), As(V), dimethyl arsenic acid, monomethyl arsenic acid, p‐arsanilic acid, and roxarsone in chicken tissues using this method were 0.012, 0.058, 0.039, 0.061, 0.102, and 0.240 mg/kg (dry weight), respectively.     

The simultaneous elimination of arsenic and mercury ions via hollow fiber supported liquid membrane and their reaction mechanisms: Experimental and modeling based on DFT and generating function

This study investigates the simultaneous removal of low concentrations of arsenic and mercury ions from synthetic produced water via hollow fiber supported liquid membrane (HFSLM). Results show that HFSLM can remove both arsenic and mercury ions from synthetic produced water to less than 0.02 and 0.001 mg·L^-1, respectively. These final concentrations comply with the wastewater standard of Thailand. Percentages of extraction for arsenic and mercury ions proved to be about 100 %. Those of recovery for arsenic and mercury ions reached 70 % and 75 %, respectively. A quantum model based on density functional theory (DFT) is introduced to analyze the forming and breaking of supramolecular complex species in the processes of extraction and recovery, respectively. Furthermore, the concept of Generating Function is applied to construct a mathematical model for forecasting the potential of removing metal ions via HFSLM. The mathematical model conforms to the experimental data, having an average relative deviation of 5 %. The results of this study provide a better understanding of the transport mechanisms of arsenic and mercury ions.     

Adsorption of arsenate on lanthanum-impregnated activated alumina: In situ ATR-FTIR and two-dimensional correlation analysis study

Lanthanum modified materials have been widely used for the removal of hazardous anions.In this study,in situ ATR-FTIR and two-dimensional correlation analysis were employed to investigate the adsorption mechanism of arsenate（As（V）） on lanthanum-impregnated activated alumina（LAA）.Our results showed that electrostatic interaction attracted As（V） anions to the LAA surface,and then As（V） could form monodentate configuration on the LAA surface at pH 5-9.The result of 2D-COS showed that two coexistent adsorbed As（V） species,H₂AsO₄^- and HAsO₄^2-,were adsorbed on the LAA surface without specific sequence at different pH conditions,indicating a negligible role of the incorporated protons of As（V） on the adsorption affinity to LAA surface.The results of this study reveal insights into LAA surface complexes on the molecular scale and provide theoretical support to new metal oxides design for efficient arsenic removal.     

ICP-AES法测定烟花爆竹药物中的砷、汞、铅

为了禁止含砷、汞、铅物质应用到烟花爆竹药物中,建立ICP-AES方法,在烟花爆竹药物经乙醇、丙酮及硝酸处理后,选用As 189.042 nm、Hg 194.227 nm、Pb 220.353 nm分析线同时测定这3种元素的含量,结果:相对标准偏差为1.97%~2.71%,回收率为98.5%~101%.方法操作简单快速,检出限低、干扰小,结果准确可靠.     

121,123Sb and 75As NMR and NQR investigation of the tetrahedrite (Cu12Sb4S13) – Tennantite (Cu12As4S13) system and other metal arsenides

This work is motivated by the recent developments in online minerals analysis in the mining and minerals processing industry via nuclear quadrupole resonance (NQR). Here we describe a nuclear magnetic resonance (NMR) and NQR study of the minerals tennantite (Cu₁₂As₄S₁₃) and tetrahedrite (Cu₁₂ Sb₄S₁₃). In the first part NQR lines associated with ⁷⁵As in tennantite and ^121,123Sb isotopes in tetrahedrite are reported. The spectroscopy has been restricted to an ambient temperature studies in accord with typical industrial conditions. The second part of this contribution reports nuclear quadrupole-perturbed NMR findings on further, only partially characterised, metal arsenides. The findings enhance the detection capabilities of NQR based analysers for online measurement applications and may aid to control arsenic and antimony concentrations in metal processing stages.     

A modified sequential extraction method for arsenic fractionation in sediments

A modified sequential extraction method was developed to characterize arsenic (As) associated with different solid constituents in surficial deposits (sediments), which are unconsolidated glacial deposits overlying bedrock. Current sequential extraction methods produce a significant amount of unresolved As in the residual fraction, but our proposed scheme can fractionate >90% of the As present in sediments. Sediment samples containing different As concentrations (3–35 μg g⁻¹) were used to assess the developed method. The pooled amount of As recovered from all the fractions using the developed method was similar (83–122%) to the total As extracted by acid digestion. The concentrations of As in different fractions using the developed scheme were comparable (89–106%) to the As fractions obtained by other existing methods. The developed method was also evaluated for the sequential extraction of other metals such as copper (Cu), cobalt (Co), chromium (Cr) and strontium (Sr) in the sediment samples. The pooled concentrations of these four individual metals from all the fractions were similar (96–104%) to their total concentrations extracted by acid digestion. During method development, we used extractants that did not contain chloride to eliminate formation of polyatomic ions of argon chloride (⁴⁰Ar³⁵Cl) that interfered with ⁷⁵As when analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The results suggest that the developed method can reliably be employed for complete As and other metals’ fractionation in sediments using ICP-MS.     

Photooxidation Of Arsenobetaine And Arsenocholine To Generate Arsines Previous To Icp-Oes Measurement

Abstract

A photolytic method, which uses UV irradiation (254 nm) and K₂S₂O₈ in alkaline media has been optimized for the speciation of arsenite, arsenate, monomethylarsonic and dimethylarsinic acid, arsenobetaine and arsenocholine. Under these conditions it is possible to obtain not only simple species from arsenobetaine and arsenocholine with good yields, but also to establish the optimum conditions to carry out the process on-line with HG-ICP/OES for the determination of these species.

The products obtained in the photolytic reaction are introduced into the reduction chamber to form arsines. According to the results obtained from the ICP measurements, the recoveries obtained are about 100% and the procedure has a good reproducibility.     

Arsenic Speciation in Marine Sediments: Effects of Redox Potential and Reducing conditions

Abstract

The speciation of arsenic in the environment is among others controlled by reduction, methylation and oxidation processes and therefore influenced by the prevailing redox conditions. In this study we have analyzed sediments taken from La Coruña estuary in the north west of Spain. Inorganic (trivalent and pentavalent) and the organic (MMA and DMA) arsenic speciation is related to Eh, Fe and Mn load. The various of the arsenic species concentration and other parameters was analyzed at different depths in some of the sampling points. Low arsenic concentrations (1–10 μg·g^–1) were found. In spite of oxidising conditions (Eh values between 31–96 mV), most of the samples showed a higher As(V) percentage than As (III). Principal component analysis was made to see a sample groups and the results showed that speciation depends on reducing conditions (Eh and Mn).     

LOW OXIDATION STATE GROUP 15 ELEMENTS AS PNICTA-WITTIG REAGENTS

We have synthesized a new As(I) salt and performed a Density Functional Theory investigation into the use of such compounds as pnicta-Wittig reagents.     

Simultaneous Determination of Arsenic and Lead in Vegetable Oil by Atomic Fluorescence Spectrometry after Vortex-Assisted Extraction

Hydride generation atomic fluorescence spectrometry (HG-AFS) is used for the determination of hydride-forming elements due to its high sensitivity, simplicity, and low cost. A new HG-AFS method for the simultaneous determination of arsenic and lead in vegetable oil is reported. Vortex-assisted extraction with dilute nitric acid was used to isolate arsenic and lead from vegetable oil. The conditions influencing the fluorescence signal, including the carrier fluid, oxidizing agent, and reducing agent, were optimized. The interferences of coexisting ions were also evaluated. Under the optimized conditions, the limits of detection were 0.6 and 0.4?µg?kg^?1 for arsenic and lead. The recoveries were from 84.4 to 105% for both metals in vegetable oil. The optimized method was used for the determination of arsenic and lead in commercial vegetable oil. The analytical results by this approach were in good agreement with values obtained by inductively coupled plasma mass spectrometry with microwave digestion.