Flow injection determination of bismuth in urine by successive retention of Bi(III) and tetrahydroborate(III) on an anion-exchange resin and hydride generation atomic absorption spectrometry
ABSTRACT Bismuth as BiCl(4)(-) and BH(4)(-) ware successively retained in a column (150mm x 4mm, length x i.d.) packed with Amberlite IRA-410 (strong anion-exchange resin). This was followed by passage of an injected slug of hydrochloric acid resulting in bismuthine generation (BiH(3)). BiH(3) was stripped from the eluent solution by the addition of a nitrogen flow and the bulk phases were separated in a gas-liquid separator. Finally, bismutine was atomized in a quartz tube for the subsequent detection of bismuth by atomic absorption spectrometry. Different halide complexes of bismuth (namely, BiBr(4)(-), BiI(4)(-) and BiCl(4)(-)) were tested for its pre-concentration, being the chloride complexes which produced the best results. Therefore, a concentration of 0.3moll(-1) of HCl was added to the samples and calibration solutions. A linear response was obtained between the detection limit (3sigma) of 0.225 and 80mugl(-1). The R.S.D.% (n = 10) for a solution containing 50mugl(-1) of Bi was 0.85%. The tolerance of the system to interferences was evaluated by investigating the effect of the following ions: Cu(2+), Co(2+), Ni(2+), Fe(3+), Cd(2+), Pb(2+), Hg(2+), Zn(2+), and Mg(2+). The most severe depression was caused by Hg(2+), which at 60mgl(-1) caused a 5% depression on the signal. For the other cations, concentrations between 1000 and 10,000mgl(-1) could be tolerated. The system was applied to the determination of Bi in urine of patients under therapy with bismuth subcitrate. The recovery of spikes of 5 and 50mugl(-1) of Bi added to the samples prior to digestion with HNO(3) and H(2)O(2) was in satisfactory ranges from 95.0 to 101.0%. The concentrations of bismuth found in six selected samples using this procedure were in good agreement with those obtained by an alternative technique (ETAAS). Finally, the concentration of Bi determined in urine before and after 3 days of treatment were 1.94 +/- 1.26 and 9.02 +/- 5.82mugl(-1), respectively.
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ABSTRACT: A rapid and simple on-line method is described for the determination of Au(III) in various samples. The method is based on the sorption of gold(III) on Lewatit MonoPlus TP 207 chelating resin including the iminodiacetate group, which is used as sorbent material and packed in a minicolumn. The chemical variables such as the pH of the sample solution, eluent type, interfering ions and concentrations of reagents, and instrumental variables such as sample loading volume, reagents flow rates, and tubing length, which affect the efficiency of the method were studied and optimised. Au(III) was sorbed on the chelating resin, from which it could be eluted with 3 mol L−1 HCl, and then introduced directly to the nebuliser-burner system of FAAS. The limit of detection of the method was 0.2 µg L−1 while the relative standard deviation was <4.0% for 20 µg L−1 Au(III) concentration. The preconcentration factor was found to be 106 while the optimised sample volume was 15.3 mL. The accuracy of the method was verified by analysing the certified reference material. The developed method was applied successfully for the determination of gold in different samples with satisfactory results.International Journal of Environmental Analytical Chemistry 07/2014; 94(9):916-929. DOI:10.1080/03067319.2014.930843 · 1.32 Impact Factor
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ABSTRACT: A new dispersive liquid–liquid microextraction (DLLME) method coupled with microvolume UV-vis spectrophotometry was developed for the determination of trace amounts of bismuth. The method is based on the complex formation of Bi(III) with iodide (BiI4�) and extraction into carbon tetrachloride as an ion pair. The extraction is assisted by methyltrioctylammonium chloride, which also acts as a disperser agent. The effect of important parameters, such as the concentration of sulfuric acid and iodide in the sample solution, the amount of methyltrioctylammonium chloride, and the type and volume of extraction solvent were investigated and optimized. The present method is capable of determining bismuth in the concentration range of 5 to 400 ng mL�1 with a limit of detection (LOD) of 1.6 ng mL�1. The relative standard deviation for eight replicate measurements of Bi(III) at concentrations of 200 and 75 ng mL�1 was calculated to be 1.14 and 2.66%, respectively. The developed method was successfully applied to the determination of bismuth in bismuth subcitrate tablets and human serum samples.Analytical methods 04/2014; 6(10):3500. DOI:10.1039/c4ay00526k · 1.94 Impact Factor
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ABSTRACT: In this work, an ion-pair dispersive liquid–liquid microextraction (IP-DLLME) procedure for the preconcentration of Bi3+ is introduced. In this procedure, 2-(5-bromo-2-pyridylazo)-5-(diethyl amino) phenol reagent as complexing agent and 700 μL of acetone (dispersing solvent) containing 75 μL of dichlorobenzene (extracting solvent) are directly injected into 10 mL of aqueous solution containing Bi3+ ions. A cloudy mixture is formed and the Bi3+ ions are extracted in fine droplets of the extracting solvent. After extraction, phase separation is performed by rapid centrifugation, and Bi3+ is determined in the enriched phase by flame atomic absorption spectrometry (FAAS). Several variable factors that influence the extraction and complex formation such as pH, concentration of 2-(5-bromo-2-pyridylazo)-5-(diethyl amino) phenol, centrifugation time, type and volume of the extracting and dispersing solvent, are optimized. Under the optimized conditions, the detection limit obtained is 3.0 ng mL−1 (3σb) and the relative standard deviation is ±1.5% (C = 0.4 μg mL−1, n = 7). The calibration curve is linear in the range of 30–1700 ng mL−1 of Bi3+ and the enrichment factor equals 28.6. The proposed method was successfully applied to the extraction and determination of Bi3+ in real and spiked samples.Journal of Analytical Atomic Spectrometry 10/2011; 26(10):2064-2068. DOI:10.1039/C1JA10131E · 3.40 Impact Factor