Simultaneous determination of arsenic,phosphorus, and silicon

Summary A simple, rapid, accurate and reliable method for the simultaneous determination of arsenic, phosphorus and silicon in the presence of each other is reported. The method involves the selective solvent extraction of phosphomolybdic acid by isobutyl acetate, the differential formation of phospho and arsenomolybdic acid when perchloric acid is added before the addition of ammonium molybdate, and the selective destruction of phospho and arsenomolybdic acid complexes in the presence of silicomolybdic acid. Silicon, phosphorus and arsenic were determined as their heteropoly blues.

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Zusammenfassung Eine einfache, rasche und verläßliche Methode zur gleichzeitigen Bestimmung von Arsen, Phosphor und Silicium nebeneinander wurde beschrieben. Phosphormolybdänsäure wird selektiv mit Isobutylacetat extrahiert. Setzt man vor der Zugabe von Ammoniummolybdat Perchlorsäure zu, so erfolgt die Bildung von Phospho- bzw. Arsenomolybdänsäure in differenter Weise. Diese beiden Säuren sind in Gegenwart von Silicomolybdänsäure selektiv zerstörbar. Silicium, Phosphor und Arsen werden auf der Grundlage der blauen Farbreaktion ihrer Heteropolysäure bestimmt.

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Résumé On communique une méthode simple, rapide, précise et sûre pour le dosage simultané de l'arsenic, du phosphore et du silicium en présence les uns des autres. La méthode met en jeu l'extraction par solvant sélectif de l'acide phosphomolybdique par l'acétate d'isobutyle, la formation différentielle de l'acide phospho et arsénomolybdique quand l'addition de l'acide perchlorique précède celle du molybdate d'ammonium, et la destruction sélective des complexes acides phospho et arsénomolybdiques en présence d'acide silicomolybdique. On a dosé le silicium, le phosphore et l'arsenic sous forme d'hétéropolycomplexes bleus.

     

Simultaneous determination of phosphorus. arsenic and germanium and the separation of silicon and arsenic by solvent extraction

A simple, rapid, accurate and reliable method for the simultaneous determination of phosphorus, arsenic and germanium as their heteropoly blue complexes is reported. The method involves selective extraction of phosphomolybdic acid at pH 1.0-0.8, and selective extraction of germanomolybdic acid by isooctyl alcohol at pH 0.4, followed by back-extraction of the germanomolybdic acid with water, and reduction of arsenomolybdic acid in the remaining aqueous phase. A rapid and reliable method is also reported for the simultaneous determination of arsenic and silicon by selective extraction of silicomolybdic acid with isooctyl alcohol at pH < 0.4 and the back-extraction of the silicomolybdic acid with water; arsenic is determined in the remaining aqueous phase. The procedure can be applied to the simultaneous determination of phosphorus, arsenic and silicon.     

Spectrophotometric determination of phosphorus and arsenic in pharmaceutical organic compounds

Summary A simple and accurate method is described for the microdeter-mination of phosphorus and arsenic in some pharmaceutical organic compounds. It is based on the conversion of phosphorus and arsenic into phosphate and arsenate ions respectively, followed by precipitation with quinoline and sodium molybdate reagents. The excess quinoline in the supernatant is spectrophotometrically measured at 312.5 nm in an ammonium acetate background of pH 5.5. The results obtained with 24 structurally different phosphorus and arsenic compounds show an average recovery of 99% and a mean standard deviation of ±1%. Excipients and diluents normally used in drug formulations do not interfere.

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Spektrophotometrische Bestimmung von Phosphor und Arsen in organischen Arzneimitteln

Zusammenfassung Eine einfache und genaue Methode zur Mikrobestimmung von Phosphor und Arsen in einigen organischen Arzneimitteln wurde angegeben. Sie beruht auf der Umsetzung des Phosphors zu Phosphat und des Arsens zu Arsenat sowie deren Fällung mit Chinolin und Natriummolybdat. Der Chinolinüberschuß wird spektrophotometrisch bei 312,5 nm in Ammonium-acetat bei pH 5,5 gemessen. Die mit 24 strukturell verschiedenen Phosphorbzw. Arsenverbindungen erhaltenen Resultate ergaben eine durchschnittliche Wiederfindungsrate von 99% und eine rel. Standardabweichung von ±1%. Arzneimittelträger und Verdünnungsmittel stören nicht.

     

Simultaneous determination of mercury and arsenic by anodic stripping voltammetry

An electrochemical method for the simultaneous determinations of Hg^II concentration and total As^III and As^V concentration has been developed. The method does not require the additional preliminary step of the chemical reduction of As^V to As^III, or oxidation of As^III to As^V before stripping analysis takes place. Also, the method for the simultaneous determination of Hg^II concentration and As^III concentration is described. Measurements were performed in 0.1 M HCl using a gold-plated graphite electrode as sensor. Detection limits for both methods are below 0.4 ppb. Relative standard deviation did not exceed 15%. The possible interference by other trace metals was investigated. Analyses of natural water and industrial solutions were made using proposed methods and AAS. The t-test demonstrates that there was no significant difference between the results obtained with these methods. Proposed methods decrease the time of analysis because concentrations of the Hg^II and arsenic ions were measured simultaneously. Also, the removal of the additional step of chemical reduction of As^V to As^III or oxidation of As^III to As^V decreases analysis time, and also reduces the chance of contamination due to the use of additional reagents.     

Simultaneous determination of aluminium and phosphorus by neutron activation analysis

With the use of the pneumatic tube system of the BER II reactor, the irradiation position of which is equipped with a movable cadmium shield, the aluminium and phosphorus levels in bone powder and in human bone biopsies were determined. The contribution of aluminium and phosphorus to the²⁸Al activity could be separated mathematically after the samples had been irradiated with and without cadmium shielding. The sensitivity and limit of quantitative determination of the analytical procedure were determined using the addition method and the fact that the levels of each element measured was independent of the amount of the other element was proved.     

Simultaneous determination of arsenic and selenium in biological samples by HG-AFS

A new method is proposed for simultaneous determination of traces of arsenic (As) and selenium (Se) in biological samples by hydride-generation double-channel non-dispersive atomic-fluorescence spectrometry (HG-AFS) from tartaric acid media. The effects of analytical conditions on fluorescence signal intensity were investigated and optimized. Interferences from coexisting ions were evaluated. Under optimum conditions linear response ranges above 20 g L^–1 for As and 32 g L^–1 for Se were obtained with detection limits of 0.13 and 0.12 g L^–1, respectively. The precision for elevenfold determination of As at the 4 g L^–1 level and of Se at the 8 g L^–1 level were 2.7 and 1.9% (RSD), respectively. Recoveries of 92.5–95.5% for As and 101.2–108.4% for Se were obtained for four biological samples and two certified biological reference materials. The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for simultaneous determination of As and Se in biological samples.     

Simultaneous determination of antimony,arsenic and copper by neutron activation analysis

A rapid procedure has been developed for the mutual separation of antimony and arsenic using tribenzylamine as the extracting agent. The extraction behaviours of Sb(III), Sb(V), As(III), As(V) and Au(III) have been studied as a function of the acidity of the aqueous phase. Various factors which affect the extraction of these complexes have been studied and optimized. The procedure was then applied to lead base alloy for the simultaneous determination of antimony, arsenic and copper. Chemical recoveries were quantitative and only about one hour is required for the chemical processing of duplicate samples.     

离子色谱-等离子体质谱联用测定热泉水样的砷形态

利用阴离子色谱与六极碰撞等离子体质谱联用的方法,在线同时测定水样的4种砷形态(As(Ⅴ),As(Ⅲ),MMA,DMA),并用于实际样品-热泉水中砷形态的测定.使用K2HPO4-KH2PO4为淋洗液等度淋洗,用Hamilton PRP-X100阴离子色谱柱分离,4种砷形态在7 min之内完全分离.调节淋洗液中K2HPO4与KH2PO4的比例可以优化峰的分离.地下水(含热泉水)基质、样品及淋洗液中的Cl-对砷形态的分离测定没有影响,淋洗液中的盐份在样品锥和截取锥上的积累对测定的影响很小.检出限分别为As(Ⅴ) 0.23 μg/L,As(Ⅲ) 0.30 μg/L,MMA 0.26 μg/L,DMA 0.54 μg/L.     

Dialkyltin salts as extractants in methods for the determination of arsenic and phosphorus

Dialkyltin salts are suitable as extractants for various oxygen-containing anions. They are particulary powerful for the extraction of arsenate and phosphate ions, but are also useful for liquid-liquid extraction of anions of dibasic acids. It is shown that the high extraction power of these dialkyltin complexes can be explained by formation of innersphere complexes with the extracted anions. A method is proposed for the separation of arsenic, phosphorus and silicon using dialkyltin salts. Applications to the extraction-spectrophotometric determination of phosphorus and arsenic in vanadium and steel, and to extraction/atomic absorption determinations of arsenic and phosphorus in metals and alloys are surveyed. The use of the dialkyltin salts for the neutron activation determination of arsenic and as active components in membranes of ion-selective electrodes for phosphorus(V) and arsenic(V) is demonstrated.     

Simultaneous determination of arsenic, selenium and antimony species using HPLC/ICP-MS

A new method for the simultaneous separation and determination of four arsenic species [As(III), As(V), monomethylarsonic acid and dimethylarsinic acid], three selenium species [Se(IV), Se(VI) and selenomethionine] as well as Sb(III) and Sb(V) is presented. The speciation was achieved by on-line coupling of anion exchange high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Chromatographic parameters such as the composition and pH of the mobile phase were optimised. Limits of detection are below 4.5 μg L^–1 (as element) for Sb(III) and the selenium species and below 0.5 μg L^–1 for the other species. Precisions of retention times were better than 2% RSD and of peak areas better than 8% RSD for all the species investigated. Received: 13 January 1999 / Accepted: 4 March 1999     

出口食用甲鱼中有害元素As、Hg的同时测定

建立了微波消解-氢化物发生原子荧光光谱法(HG-AFS)同时测定出口食用甲鱼中As、Hg残留量的方法,并对HG-AFS工作参数及条件进行了优化和选择。As检出限为0.056μg/L,Hg检出限为0.0071μg/L;相对标准偏差As为0.4%(n=11,ρAs=20μg/L),Hg为0.7%(n=11,ρHg=10μg/L);回收率范围为92%~99%。本法已用于出口食用水生活甲鱼中As、Hg残留量的检测。     

Simultaneous determination of arsenic, selenium and antimony species using HPLC/ICP-MS

A new method for the simultaneous separation and determination of four arsenic species [As(III), As(V), monomethylarsonic acid and dimethylarsinic acid], three selenium species [Se(IV), Se(VI) and selenomethionine] as well as Sb(III) and Sb(V) is presented. The speciation was achieved by on-line coupling of anion exchange high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Chromatographic parameters such as the composition and pH of the mobile phase were optimised. Limits of detection are below 4.5 μg L^–1 (as element) for Sb(III) and the selenium species and below 0.5 μg L^–1 for the other species. Precisions of retention times were better than 2% RSD and of peak areas better than 8% RSD for all the species investigated.     

Simultaneous determination of arsenic species by ion chromatography-inductively coupled plasma mass spectrometry

Six arsenic species, arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine, were separated by coupled column ion chromatography using carbonate and nitric acid as eluents, and were detected by inductively coupled plasma mass spectrometry. Coupling of an anion column with a cation column made the simultaneous determination of both the cationjic and the anionic arsenic species possible by ion chromatography. Extremely low detection limits, below 0.2 μg/1 (as arsenic), were obtained for all the species studied.     

A new reagent for the colorimetric and spectrophotometric determination of phosphorus,arsenic and germanium

A new reagent for the colorimetric and spectrophotometric determination of phosphorus, arsenic and gurmanium is described. It contains Mo(Vl) amd Mo(V) in the ratio of 3 : 2 in an acid medium, 10N with respect to H₂SO₄ and 3N with respect to HCl.The absorption spectra, the influence of temperature, time, quantity of reagent and selectivity of the method have been studied. Beer's law is applicable up to 160 μg for P₂O₅, 220 μg for GeO₂ and 230 μg for arsenic, in 50 ml.     

Simultaneous determination of arsenic and antimony in environmental samples by radiochemical neutron activation analysis

A radiochemical separation procedure using an inorganic exchanger, tin dioxide (TDO), for the separation of arsenic from antimony is reported here. This separation avoids the interference of 564 keV gamma-ray of¹²²Sb in the measurement of the 559 keV gamma-ray of⁷⁶As in neutron activation analysis. Environmental samples, after neutron irradiation and digestion, are taken up in 1M HCl–0.1M HF and passed through a TDO column which selectively retains arsenic. The effluent from the TDO column, after proper conditioning, is passed through an anion exchange column for quantitative retention of antimony. The procedure has been utilized for arsenic and antimony determination in NBS Orchard Leaves and NBS Albacore Tuna.     

Simultaneous determination of silicon and phosphorus in soil and plants by reversed-phase ion-pair chromatography

A reversed-phase ion-pair high-performance liquid chromatographic method, using tetrabutylammonium bromide (TBABr) as ion-pair reagent, has been developed for the simultaneous analysis of silicon (Si) and phosphorus (P) as heteropoly acids in soil and plant samples. The effect of the concentrations of ion-pair reagent, acetate buffer and organic modifier as well as the pH of buffer on separation was made clear. The reaction conditions and stability of heteropoly acids were investigated. Furthermore, the phenomenon occurred in the optimized process was also further researched. The separation was performed on a reversed-phase C(18) column within 11 min with 40:60 (v/v) 0.1M acetate buffer (pH 3.9)-acetonitrile (ACN) containing 0.8 mM TBABr as a mobile phase. The linear ranges of the peak area calibration curves for Si and P were 0.08-50 mg/L and 0.40-50 mg/L, respectively. The detection limits calculated at S/N=3 were 0.0057 mg/L and 0.0280 mg/L for Si and P, respectively. The method was successfully applied to the analysis of soluble and total contents of Si and P in soil and plant samples.     

Simultaneous determination of arsenite and arsenate in arsenic trioxide injection by dual detection ion chromatography

This paper describes a rapid method to determine arsenite assay and arsenate impurity in Arsenic Trioxide Injection using a single conductivity detector. The arsenite assay was determined in a non-suppressed conductivity detection mode and arsenate impurity was quantified in a suppressed conductivity detection mode. Dual-conductivity detections were enabled by valve switching and time programming. The method was validated with respect to specificity, linearity, precision, accuracy, stability, and limit of quantification. The limit of detection and quantification for arsenite were 0.855 mg/L and 2.593 mg/L, and 0.044 mg/L and 0.133 mg/L for arsenate, respectively.