Outline

  • Abstract
  • Keywords
  • 1. Introduction
  • 2. Experimental
  • 2.1. Apparatus
  • 2.2. Reagents
  • 2.3. Procedures
  • 2.3.1. Extraction Behavior of Gold(iii) with Some Amine Compounds
  • 2.3.2. Determination of Gold by Etaas After Dllme Using Dicyclohexylamine
  • 3. Results and Discussion
  • 3.1. Extraction of Gold(iii) with Some Amine Compounds
  • 3.1.1. Comparison of Extraction Behavior of Gold(iii) by Lle and Dllme
  • 3.1.2. Role of Acetone on Extraction of Gold(iii) with Dicyclohexylamine
  • 3.2. Optimum Conditions for Dllme of Gold(iii) with Dicyclohexylamine
  • 3.2.1. Water-Miscible Organic Solvent
  • 3.2.2. Water-Immiscible Organic Solvent As Extraction Solvent
  • 3.2.3. Dicyclohexylamine
  • 3.2.4. Extraction Time
  • 3.2.5. Extraction Ph
  • 3.2.6. Selectivity
  • 3.3. Calibration Curve and Detection Limit
  • 3.4. Interference
  • 3.5. Application
  • 4. Conclusion
  • Acknowledgements
  • Appendix A. Supplementary Data
  • References

رئوس مطالب

  • چکیده
  • کلید واژه ها
  • 1. مقدمه
  • 2. مواد و آزمایش
  • 2.1. دستگاه
  • 2.2. واکنشگرها
  • 2.3. روش کار
  • 2.3.1. شیوه ی استخراج طلا (III) با برخی از ترکیبات آمینی
  • 2.3.2. تعیین طلا بوسیله ی ETAAS پس از DLLME با استفاده از دی سیکلو هگزیل آمین
  • 3. نتایج و بحث
  • 3.1. استخراج طلا (III) با استفاده از برخی ترکیبات آمینی
  • 3.1.1. مقایسه شیوه ی استخراج طلا (III) توسط LLE و DLLME
  • 3.1.2. نقش استون در استخراج طلا (III) با استفاده از دی سیکلو هگزیل آمین
  • 3.2. شرایط بهینه برای DLLME طلا (III) با دی سیکلو هگزیل آمین
  • 3.2.1. حلال آلی امتزاج پذیر با آب
  • 3.2.2. حلال های آلی امتزاج ناپذیر با آب به عنوان حلال استخراجی
  • 3.2.3. دی سیکلو هگزیل آمین
  • 3.2.4. زمان استخراج
  • 3.2.5. pH استخراج
  • 3.2.6. گزینش پذیری
  • 3.3. منحنی کالیبراسیون و حد تشخیص
  • 3.4. تداخل
  • 3.5. کاربرد
  • 4. نتیجه گیری

Abstract

A combined method with dispersive liquid–liquid microextraction (DLLME) and electrothermal atomic absorption spectrometry (ETAAS) has been developed for determining gold(III). Dicyclohexylamine, a new extractant for gold(III), showed excellent performance in DLLME. Acetone was indispensable to the quantitative extraction of gold(III), contributing to decrease in hydration, decrease in the difference in the dielectric constants between the supernatant phase and the sedimented phase, and dissolution of a part of chloroform as an extraction solvent to the supernatant phase as well as improvement of dipersibility. In DLLME using a mixture of 1.0 mL of acetone and 100 μL of chloroform containing 50 mmol L−1 of dicyclohexylamine, gold(III) could be extracted selectively and effectively from 8 mL of a sample solution in the presence of iron(III), cobalt(II), nickel(II), copper(II), palladium(II), and platinum(IV) at pH 1. The extracted gold(III) was determinable by ETAAS; the detection limit was 0.002 μg L−1 (three times the standard deviation of the blank values, n = 8) as a gold(III) concentration in 8 mL of sample solution. The proposed method was applicable to the determination of gold in platinum metal and its alloy as well as effluent without any interference by the matrices.

Keywords: - - - -

Conclusions

preconcentration of some elements [14–17], but there has been no report on the separation and preconcentration of gold(III). Dispersive liquid–liquid microextraction (DLLME) [18] has also attracted attention recently [19–27]. In DLLME, as in HoLLE, an aqueous sample solution, a water-miscible organic solvent as the disperser solvent, and a water-immiscible organic solvent as the extraction solvent are used; however, the extraction solvent has only to disperse finely into solution. In general, a mixture of disperser solvent and extraction solvent is swiftly injected using a microsyringe, and a gentle shaking is applied to extract the analyte quantitatively into the dispersed extraction solvent. The selection of a dispersive solvent which gives favorable dispersibility of the extraction solvent is important to achieve effective extraction of analyte [18–27]. DLLME is conveniently applicable to the separation and preconcentration of various elements prior to their ETAAS determination [19–27]; for gold(III), however, only DLLME using victoria blue R has been reported [25]. In this work, we investigated a combined method with DLLME and ETAAS for determining gold(III). For DLLME using acetone as a water-miscible organic solvent and chloroform as a water-immiscible organic solvent, we tested 11 kinds of amine compounds as extractants and found that dicyclohexylamine, which has not been used for the extraction of gold(III), was excellent. It is noteworthy that DLLME using dicyclohexylamine has rather high selectivity; gold(III) could be determined by ETAAS without any interference even in the presence of large amounts of other elements. In this paper, we report the results of investigations of the DLLME of gold(III) with amine compounds and discuss the role of acetone as a water-miscible organic solvent in the extraction of gold(III) with dicyclohexylamine. The potential of ETAAS combined with DLLME using dicyclohexylamine is also demonstrated through the determination of gold in effluent, platinum metal, and platinum alloy.

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