A Coulometric Analysis Method and an Ion-exclusion Chromatographic Method for the Determination of Antimony(V) in Large Excess of Antimony(III)

A coulometric analysis method and an ion-exclusion chromatographic method were developed for the determination of antimony(V) in a large excess of antimony(III). Antimony(V) reacted with potassium iodide in a high concentration hydrochloric acid; the liberated iodine was determined by the standard-addition method using coulometrically generated iodine. Using a Dionex ICE-AS1 ion-exclusion column, antimony(V) was eluted with 40 mmol/L sulfuric acid; on the other hand, antimony(III) was strongly retained on the column. The content, expressed as the amount ratio of antimony(V) to antimony(III), was 0.035% in a 10 g/kg antimony(III) solution prepared from an antimony(III) oxide reagent by the coulometric analysis method and 0.036% in a 1 g/kg antimony(III) solution prepared from the same antimony(III) oxide by the ion-exclusion chromatographic method. The results of both methods were in good agreement with each other. The detection limit of antimony(V) in antimony(III) oxide by the former method was 0.004% of antimony(III), and that by the latter method was 0.002% of antimony(III).     

Simultaneous determination of inorganic and organic antimony species by using anion exchange phases for HPLC-ICP-MS and their application to plant extracts of Pteris vittata

Antimony is a common contaminant at abandoned sites for non-ferrous ore mining and processing. Because of the possible risk of antimony by transfer to plants growing on contaminated sites, it is of importance to analyze antimony and its species in such biota. A method based on high performance liquid chromatographic separation and inductively coupled plasma mass spectrometric detection (HPLC-ICP-MS) was developed to determine inorganic antimony species such as Sb(III) and Sb(V) as well as possible antimony-organic metabolisation products of the antimony transferred into plant material within one chromatographic run. The separation is performed using anion chromatography on a strong anion exchange column (IonPac AS15/AG 15). Based on isocratic optimizations for the separation of Sb(III) and Sb(V) as well as Sb(V) and trimenthylated Sb(V) (TMSb(V)), a chromatographic method with an eluent gradient was developed. The suggested analytical method was applied to aqueous extracts of Chinese break fern Pteris vittata samples. The transfer of antimony from spiked soil composites into the fern, which is known as a hyperaccumulator for arsenic, was investigated under greenhouse conditions. Remarkable amounts of antimony were transferred into roots and leaves of P. vittata growing on spiked soil composites. Generally, P. vittata accumulates not only arsenic (as shown in a multiplicity of studies in the last decade), but also antimony to a lower extent. The main contaminant in the extracts was Sb(V), but also elevated concentrations of Sb(III) and TMSb(V) (all in μg L⁻¹ range). An unidentified Sb compound in the plant extracts was detected, which slightly differ in elution time from TMSb(V).     

Determination of Phosphorus in Chlorosilanes) And High Purity Silica By Atomic Absorption Spectrophotometer

Abstract

Determination of traces of impurities in chloro-silanes and high purity silica are important in the preparation of semiconductor grade silicon. The author have developed an indirect method for the determination of phosphorus in these materials. Phosphorus is extracted as phosphoantimonyl molybdate complex in methyl isobutyl ketone. The concentration of phorphorus is calculated by determining the concentration of antimony by atomic absorption spectrophotometer as antimony and phosphorus are present in 1:1 molar ratio in the complex. The method is selective and enables the determination of 0.1 ppm of phosphorus.     

Determination of antimony content in natural water by graphite furnace atomic absorption spectrometry after collection as antimony(III)-pyrogallol complex on activated carbon

Antimony(III) was preconcentrated on activated carbon (AC) as the antimony(III)–pyrogallol complex. Prior to the preconcentration, antimony(V) was reduced to antimony(III) with potassium iodide and ascorbic acid. The antimony adsorbed on the AC was determined by graphite furnace atomic absorption spectrometry as an AC suspension. The method was applied to differential determination of trace amounts of antimony in natural water.     

Speciation Analysis of Antimony (III) and Antimony (V) by Flame Atomic Absorption Spectrometry After Separation/Preconcentration With Cloud Point Extraction

A sensitive and simple method for flame atomic absorption spectrometry (FAAS) determination of antimony species after separation/preconcentration by cloud point extraction (CPE) has been developed. When the system temperature is higher than the cloud point extraction temperature, the complex of antimony (III) with N-benzoyl-N-phenyhydroxylamine (BPHA) can enter the surfactant-rich phase, whereas the antimony (V) remains in the aqueous phase. Antimony (III) in surfactant-rich phase was analyzed by FAAS and antimony (V) was calculated by subtracting of antimony (III) from the total antimony after reducing antimony (V) to antimony (III) by L-cysteine. The main factors affecting the cloud point extraction, such as pH, concentration of BPHA and Triton X-114, equilibration temperature and time, were investigated systematically. Under optimized conditions, the detection limits (3σ) were 1.82 ng mL⁻¹ for Sb(III) and 2.08 ng mL⁻¹ for Sb(total), and the relative standard deviations (RSDs) were 2.6% for Sb(III) and 2.2% for Sb(total). The proposed method was applied to the speciation of antimony species in artificial seawater and wastewater, and recoveries in the range of 95.3–106% were obtained by spiking real samples. This technique was validated by means of reference water materials and gave good agreement with certified values.     

Capillary Melt Method for Micro Antimony Oxide pH Electrode

In this work, a new approach named “capillary melt method” was developed to fabricate micro antimony wires, and the wire surface was then oxidized in a nitrate melt at high temperature to obtain an antimony/antimony oxide pH electrode. Characterization results show that the oxide layer on the wire surface is porous, and consists of Sb₂O₃ crystal phase. The pH electrode, made using this method, showed good sensing performance in buffer solutions in the tested pH range of 2–12. Its EMF signal was found to have a linear relationship with pH value of the solution, with a sensitivity of 54.1 mV/pH and a fitting correlation coefficient of R²=1.00. The advantages of the electrode are long‐term stability, fast response, reproducibility and low cost.     

Simultaneous determination of copper,mercury and antimony in biological samples by neutron activation and substoichiometric extraction

A simple and accurate method has been developed for the determination of copper, mercury and antimony by thermal neutron activation analysis involving substoichiometric extraction technique. The results of analysis indicate that copper, mercury and antimony in biological samples can be determined with an accuracy of 5.3%, 5.5% and 6.2%, respectively. Two samples and a standard can be analysed by the proposed method in about 4 hrs. Part of this work was presented at the International Conference on Modern Trends in Activation Analysis, Saclay, Paris, France, October 2–6, 1972.     

微型氢化物发生-原子吸收光谱法测定纺织品中的痕量砷和锑

采用三毛细管微型在线氢化发生技术和装置, 建立了氢化物发生-电热石英管原子吸收法测定纺织品中痕量As、 Sb的分析方法. 研究了共存离子对As、 Sb检测的干扰及消除方法. 结果表明: 该方法除Co、 Sn对As和Ni对Sb有干扰外, 其它干扰元素允许量都较大. 采用酒石酸和KI混合掩蔽剂可抑制Co、 Sn对As和Ni对 Sb的干扰. As和Sb的检出限分别为0.7和0.4 ng/L, 已用于测定纺织品中痕量As和Sb的分析.     

Solidified floating organic drop microextraction–electrothermal atomic absorption spectrometry for ultra trace determination of antimony species in tea, basil and water samples

Solidified floating organic drop microextraction was applied as a separation/preconcentration step prior to the electrothermal atomic absorption spectrometric (ETAAS) determination of ultra trace of antimony species. The method was based on the formation of an extractable complex between Sb(III) and ammonium pyrrolidinedithiocarbamate at pH ~ 5, while Sb(V) was remained in the aqueous phase. The antimony extracted into 1-undecanol was determined by ETAAS. Total antimony was determined after the reduction of Sb(V) to Sb(III) with potassium iodide and ascorbic acid. The amount of Sb(V) was determined from the difference of concentration of total antimony and Sb(III). Under the optimum conditions an enhancement factor of 437.5 and a detection limit of 5.0 ng L^?1for the preconcentration of 25 mL of sample was achieved. The relative standard deviation at 300 ng L^?1 of antimony was found to be 3.5 % (n = 6). The proposed method was successfully applied to the determination of antimony in tea, basil and natural water samples.     

Graphene Oxide‐Modified Electrode Coated with in‐situ Antimony Film for the Simultaneous Determination of Heavy Metals by Sequential Injection‐Anodic Stripping Voltammetry

The proposed chemically modified electrode was graphene oxide that was synthesized via Hummer's method followed by reduction of antimony film by in‐situ electrodeposition. The experimental process could be concluded in three main steps: preparation of antimony film, reduction of analyte ions on the electrode surface and stripping step under the conditions of square wave anodic stripping voltammetry (SWASV). A simple and rapid approach was developed for the determination of heavy metals simultaneously based on a sequential injection (SI), an automated flow‐based system, coupled with voltammetric method using antimony‐graphene oxide modified screen‐printed carbon electrode (SbF‐GO‐SPCE). The effects of main parameters involved with graphene oxide, antimony and measurement parameters were also investigated. Using SI‐SWASV under the optimal conditions, the proposed electrode platform has exhibited linear range from 0.1 to 1.5 M. Calculated limits of detection were 0.054, 0.026, 0.060, and 0.066 μM for Cd(II), Pb(II), Cu(II) and Hg(II), respectively. In addition, the optimized method has been successfully applied to determine heavy metals in real water samples with acceptable accuracy of 94.29 – 113.42 % recovery.     

Determination of Inorganic Sb(V) and Methylantimony Species by HPLC with Hydride Generation-Atomic Fluorescence Spectrometric Detection

 An on-line method for the separation and analysis of Sb(V) and Me₃Sb in the presence of Sb(III) in liquid samples is described. Inorganic and organic antimony species were separated using anion-exchange high-performance liquid chromatography (HPLC) coupled with hydride generation-atomic fluorescence detection (HG-AFS). Optimum conditions for the separation of antimony species by HPLC and the hydride generation conditions for the determination by HG-AFS were established. Matrix interference of the chromatographic determination was studied in relation to MgSO₄ and NaCl. The method developed was applied to the separation and determination of antimony species in spiked and natural water samples. The suitability of the method for analysis in microbial growth media and physiological studies involving methylantimony species is discussed. Received December 11, 2000. Revision April 26, 2001.     

Headspace single-drop microextraction with in situ stibine generation for the determination of antimony (III) and total antimony by electrothermal-atomic absorption spectrometry

A headspace-single drop microextraction method combined with electrothermal atomic absorption spectrometry (ETAAS) is developed for the extraction and preconcentration of antimony(III) and total antimony into a Pd(II)-containing aqueous drop after hydride generation. Experimental variables such as hydrochloric acid and sodium tetrahydroborate concentrations, sample volume, Pd(II) concentration in the acceptor phase and microextraction time were optimized. A 2^6-2 _IV factorial fractional design was initially used for screening the effect of the variables, followed by an univariate approach. The method showed a great freedom from interferences caused by hydride-forming elements and transition metals. The detection limit of Sb(III) was 25 pg mL^?1. A preconcentration factor of 176 is achieved in 3 min. The repeatability, expressed as relative standard deviation, was 4.7%. The method was validated against two certified reference materials (NWRI-TM 27.2 and NIST 2711) and applied to the determination of Sb(III) and total Sb in waters.     

Speciation of Antimony in Leaching Solution in Contact with Plastic by Novel Liquid-Liquid Microextraction and Graphite Furnace Atomic Absorption Spectrometry

A novel, simple, sensitive, and efficient method for the speciation of inorganic antimony by dispersive liquid–liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectrometry (GF-AAS) is reported. The method uses a hydrophobic complex of antimony(III) with a new chelating agent, 1,2,6-hexanetriol trithioglycolate, at neutral pH. The complex was extracted into the organic phase, whereas antimony(V) remained in aqueous solution. The concentration of antimony(V) was obtained by subtracting the antimony(III) concentration from the total antimony concentration following the reduction of antimony(V) to antimony(III) by L-cysteine. The pH, extraction and dispersive solvents and volumes, and concentration of 1,2,6 -hexanetriol trithioglycolate were optimized. Under the optimized conditions, the analytical curve was linear from 0.26 to 3.2 micrograms per liter with a limit of detection of 27.0 nanograms per liter for antimony(III). The relative standard deviation was 6.8 percent at 0.52 microgram per liter antimony(III) with an enrichment factor of twenty-six. The method was employed for the speciation of antimony in leaching solution in contact with plastic; and the recoveries in fortified samples were between 94.2 and 118.0 percent.     

Quality assurance system for a decomposition method as demonstrated for the Wickbold combustion technique

 A five-step model for a quality assurance system is developed for an internal quality control check. It includes the quality control of the decomposition method and the detection method as steps belonging together. The Wickbold combustion technique as decomposition method in combination with atomic absorption spectrometry was chosen. The vaporization of the elements mercury, arsenic, lead, antimony and selenium is based on combustion in an oxyhydrogen flame. To check the efficiency of the analytical system, the uncertainty of results was calculated on the basis of the "Guide to the Expression of Uncertainty in Measurement". Received: 13 January 1997 · Accepted: 29 March 1997     

Determination of antimony and tin in tin dioxide whiskers by inductively coupled plasma mass spectrometry

A procedure for the determination of antimony and tin in tin dioxide whiskers, which were grown from a gas phase by the vapor-liquid-solid mechanism, was developed. The problem was difficult because the single whiskers are irregularly small in size and have a small weight (about 10^?5 g). The procedure is based on the decomposition of a solid sample by cementation on zinc followed by the determination of analytes with the use of inductively coupled plasma mass spectrometry. The procedure developed is characterized by the detection limits of antimony of 0.01–0.03 μg/L and an RSD of 10%. An approach was proposed to estimate the antimony content of single whiskers.     

X射线荧光光谱法同时快速测定锑矿石中伴生及有害元素

采用粉末压片制样,波长色散型X射线荧光光谱法测定锑矿石中9个次量伴生及有害元素Cu、Pb、Zn、As、Co、Ni、W、Ba、S.选用国家标准物质和人工合成标准参考物质建立校准工作曲线,采用经验系数法和散射线内标法校正基体效应和元素重叠干扰.方法的检出限低、精密度(RSD,n=12)小于5%,测定结果与参考值或化学值一致性良好.与化学法相比,操作简单、快速、准确度高,精密度好,有效解决化学法在锑矿石伴生、有害等微量组分分析中过程烦琐、干扰严重等问题.     

Continuous flow hydride generation for the preconcentration and determination of arsenic and antimony by GFAAS

A method has been developed for the determination of arsenic and antimony at sub-ppb level using hydride preconcentration inside the graphite furnace. The influence of the quality of the graphite surface, of its modification with palladium coating and of the ways of introducing hydride into the furnace on the analytical signal is discussed. After optimization of system parameters, detection limits of 25 and 36 pg were obtained for arsenic and antimony. Characteristic masses (for arsenic and antimony, respectively) were 31 and 33 pg/0.0044 A·s for direct injection GFAAS and 69 and 57 pg/0.0044 A·s for hydride in situ preconcentration and atomization in the palladium coated graphite tube. Therefore the overall efficiency of the hydride generation and trapping was estimated to be 45 and 58% for arsenic and antimony, respectively.     

Determination of iron and antimony by radiochemical displacement of60Co from cobalt-o-hydroxybenzaldehyde isonicotinoyl hydrazone

A radiochemical displacement method has been developed for the determination of 10 g amounts of iron and antimony. The effect of pH and various foreign ions on the displacement of tracer⁶⁰Co from labeled Co-o-Hydroxybenzaldehyde isonicotinoyl hydrazone (BIH) complex in isoamyl alcohol by iron and antimony was studied.     

The use of rhodamine .B in analytical chemistry: The determination of small quantities of gold

Using the technique already developed for determination of antimony with rhodamine B a method has been derived for determining small quantities of gold in the range 0–30 μg. Owing to the stability of the higher valency of gold no oxidation stage is required; extraction of the complex is only satisfactory with isopropyl ether in contrast with the case of antimony which gives good results with benzene as well as the isopropyl ether.     

Antimony (III) Sulfate Catalyzed One-Pot Synthesis of 2,3-Disubstitutedindoles

A novel one-pot Fischer indole synthesis approach has been developed by using antimony (III) sulfate as the catalyst. Good yields were obtained after reacting phenylhydrazines hydrochlorides and ketones in refluxing methanol. The exclusive formation of 2,3- disubstituted indoles was observed in the reaction of ethyl methyl ketone with phenylhydrazines. One-pot synthesis of indole-3-propanol using dihydropyran has also been described. The use of reusable antimony (III) sulfate as a catalyst makes this method both economically and environmentally friendly.