Trace Amounts Of Antimony Research Articles

Moisture‐Insensitive, Phase‐Stable Indium‐Based Metal Halides and Their Light‐Emitting Applications

AbstractTernary indium (In)‐based metal halides are gaining increased attention as promising lead (Pb)‐free alternatives for light‐emitting diodes (LEDs) owing to their broadband emission and high photoluminescence quantum yields (PLQYs). However, most of the pure In‐based compositions suffer from instability against moisture and thermal stress, leading to a rapid degradation of material and hence their optical properties. Herein, a new kind of organic–inorganic hybrid In‐based metal halide BA6InCl9 (BA+ = C4H11N+) is presented, which exhibits stable crystal structure and material composition at both ambient (over 5 months) and heating conditions (up to 200 °C). Besides, the Huang‐Rhys factor of ≈4.94 determined for BA6InCl9 is considerably smaller than most Pb‐free perovskites, which suggests a relatively weak exciton‐phonon coupling in these crystals. By trace amounts of antimony (III) (Sb3+) doping, the PLQY of the BA6InCl9 single crystals can be markedly improved from ≈25% to 95%, and the ensuing down‐conversion LEDs exhibit bright orange‐red emission with an external quantum efficiency of 0.12%, which retains ≈50% of the initial luminance after 380 min of continuous operation in ambient air. It is forseen that the study will prompt future research on In‐based metal halides and their use in stable light‐emitting applications.

Identification of amino acid substitutions that toggle substrate selectivity of the yeast arsenite transporter Acr3

The Acr3 protein family plays a crucial role in metalloid detoxification and includes members from bacteria to higher plants. Most of the Acr3 transporters studied so far are specific for arsenite, whereas Acr3 from budding yeast also shows some capacity to transport antimonite. However, the molecular basis of Acr3 substrate specificity remains poorly understood. By analyzing randomly generated and rationally designed yeast Acr3 variants, critical residues determining substrate specificity were identified for the first time. Replacement of Val173 with Ala abolished antimonite transport without affecting arsenite extrusion. In contrast, substitution of Glu353 with Asp resulted in a loss of arsenite transport activity and a concomitant increase in antimonite translocation capacity. Importantly, Val173 is located close to the hypothetical substrate binding site, whereas Glu353 has been proposed to participate in substrate binding. Identification of key residues conferring substrate selectivity provides a valuable starting point for further studies of the Acr3 family and may have implications for the development of biotechnological applications in metalloid remediation. Moreover, our data contribute to understanding why members of the Acr3 family evolved as arsenite-specific transporters in an environment of ubiquitously present arsenic and trace amounts of antimony.

Application of ultrasound-assisted emulsification microextraction for spectrophotometric determination of trace amounts of antimony(v) in drinking water samples using rhodamine B

Ultrasound-assisted emulsification microextraction (USAE-ME) procedure has been applied for preconcentration and spectrophotometric determination of antimony(V) in water samples. The method is based on the ion-pair formation of hexachloroantimonate with rhodamine B in acidic medium, followed by USAE-ME of the formed ion-pair into fine droplets of the organic phase for spectrophotometric detection. Experimental parameters for both the spectrophotometric reaction and the USAE-ME procedure have been optimized. Under the optimum conditions, the calibration graph was linear over the range 5.0–300.0 ng mL−1 of Sb(V) (R2 = 0.998). The detection limit (3Sb) and preconcentration factor were 0.6 ng mL−1 and 40, respectively. The relative standard deviation (RSD) for five replicate determinations of Sb(V) at 100.0 ng mL−1 concentration level was calculated to be 2.4%. The proposed method has been successfully applied to the determination of antimony(V) in different water samples and good spiked average recovery of 98.3% was obtained.

Zinc electrowinning from acidic sulphate solutions. Part III: Effects of quaternary ammonium bromides

The effects of the organic additives cetyltrimethylammonium bromide (CTABr) and tetrabutyl ammonium bromide (TBABr) on the electrowinning of zinc from acidic sulphate solutions were studied in the presence and absence of trace amounts of antimony(iii). The results indicated that CTABr has similar properties to the commonly used industrial additive glue with respect to current efficiency, power consumption, polarization behaviour, and the crystallographic orientation and surface morphology of the zinc deposits. TBABr was generally less useful with respect to all these properties. Voltammetric studies indicate that polarisation for zinc electrodeposition decreased in the order CTABr > glue > TBABr. The nature of the electrode reactions were investigated through measurements of exchange current densities, Tafel slopes and transfer coefficients.

Determination of (ultra)trace amounts of antimony(III) in water by flow injection on-line sorption preconcentration in a knotted reactor coupled with electrothermal atomic absorption spectrometry

A flow injection on-line sorption preconcentration system has been synchronously coupled to an ETAAS system for the selective determination of (ultra)trace amounts of SbIII in water. The determination was achieved by selective complexation of SbIII with ammonium pyrrolidine dithiocarbamate (APDC) at a wide range of sample acidity (0–1 mol l–1 HCl), sorption of the complex onto the inner walls of a knotted reactor made from (100 cm long × 0.5 mm id) PTFE tubing, quantitative elution with 35 µl of ethanol and subsequent ETAAS detection. In order to minimize dispersion and to reduce the eluent volume required for the quantitative elution, an air flow was used to drive the eluent elution and to deliver all the eluate into an unpreheated polycrystalline graphite tube without a platform. Precise timing was not needed for analyte elution and eluate introduction. ETAAS determination of the analyte was performed in parallel with the preconcentration of the next sample. Using a preconcentration time of 30 s and a sample loading flow rate of 5.4 ml min–1, an enhancement factor of 30 was obtained in comparison with direct injection of 35 µl aqueous solution, resulting in a sampling frequency of 42 samples h–1. The detection limit (3s) was 0.021 µg l–1 and the precision was 2.9%(RSD) for eleven replicate determinations at 1 µg l–1. The introduction of an efficient wash step before elution with the addition of APDC to the wash medium permitted the use of simple aqueous standards for direct calibration in the analysis of sea-water. The accuracy of the proposed method was demonstrated by analysing synthetic mixtures and spiked sea-water.

Kohl: a lead-hazardous eye makeup from the Third World to the First World.

Kohl is a widely used traditional cosmetic. It is mainly worn around the eyes in Asia, Africa, and the Middle East. It may be a pervasive source of lead poisoning in those areas and among individuals from those areas who have immigrated to developed nations. Samples of kohl were purchased in Morocco, Mauritania, Great Britain, and the United States. Some of these samples originated from Pakistan, India, and Saudi Arabia. Kohl is widely believed to consist of antimony, but analysis consistently revealed only trace amounts of antimony. Nine of the twenty-two samples tested contained less than 0.6% lead; however, seven samples had lead levels in excess of 50%. The remainder ranged from 3.31 to 37.3%. Third-world-manufactured kohls were purchased in the United States and Britain, suggesting that this hazard is no longer confined to the third world. Those kohls that contained lead were sold in violation of laws on lead in cosmetics in both of these nations. Third-world physicians and health care workers appear to be unaware of possible lead uptake from unsuspected traditionally used items. Physicians in developed nations with patients from Asia, the Middle East, and North Africa need to factor in the possibility of past or present lead intake from unorthodox sources such as kohl.

A critical study of safranine O as a spectrophotometric reagent: a rapid method for the determination of trace amounts of antimony in steel

The behaviour of Safranine O (Basic red 2, C.I. 50240) in aqueous solutions has been investigated and its suitability as a spectrophotometric reagent is evaluated and discussed. A rapid method for the determination of antimony as a hexachloroantimonate(V) ion-association complex with Safranine O is described. This complex is extracted into benzene and is determined spectrophotometrically. The method is as sensitive and reproducible as the Rhodamine B method but it has the advantage that the determination can be carried out directly on solutions of steel without prior separation. Good agreement was found with standardised antimony values for five British Chemical Standards' steels.

塩化ヒ素(III)精製時の微量アンチモン,セレンの挙動

塩化ヒ素(III)精製時の微量アンチモン,セレンの挙動