A sensitive and selective method for determination of gold(III) based on electrothermal atomic absorption spectrometry in combination with dispersive liquid–liquid microextraction using dicyclohexylamine

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 1.0mL of acetone and 100microL of chloroform containing 50mmolL(-1) of dicyclohexylamine, gold(III) could be extracted selectively and effectively from 8mL 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 0.002microgL(-1) (three times the standard deviation of the blank values, n=8) as a gold(III) concentration in 8mL 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.

Liquid-phase microextraction combined with graphite furnace atomic absorption spectrometry: A review

“…Typical strategies for determining metal ions, metalloids and organometallic compounds by LPME-GFAAS involve the formation of hydrophobic metal complexes [10, 45,58,59] or ion pairs [60] in the sample solution. In these cases, a careful control of the sample pH prior to the LPME process is a basic requirement to achieve the highest sensitivity.…”

“…For industrial sludge, ultrasound-assisted acid extraction using 25% v/v HNO 3 + 25% v/v HCl mixture was applied before Au preconcentration by DLLME [157]. Effluent samples originated from a jewelry factory, were digested with HCl upon heating followed by membrane filtration [60].…”

Ion-association dispersive liquid–liquid microextraction of ultra-trace amount of gold in water samples using Aliquat 336 prior to inductively coupled plasma atomic emission spectrometry determination

“…The word noble refers in part to its rarity, beauty, and wide utility in economic and industrial activity due to its chemical stability, high ductility, corrosive resistance, and low impedance (Kagaya et al 2010). The average concentration of gold in earth's crust is approximately 4 μg kg −1 (ppb) and the values of 0.05 and 0.2 ng mL −1 (ppb) were found in sea water and river water, respectively (Lee 1996;Rancis et al 2005).…”

Ion Pair-Dispersive Liquid-Liquid Microextraction Coupled to Microsample Injection System-Flame Atomic Absorption Spectrometry For Determination of Gold at Trace Level in Real Samples

“…2 Thus an accurate, sensitive and selective analytical method is required for gold determination. A wide variety of analytical techniques such as flame atomic absorption spectrometry (FAAS), 3,4 electrothermal atomic absorption spectrometry (ETAAS), 5,6 inductively coupled plasma atomic emission spectrometry (ICP-AES) 7,8 and spectrophotometry 9,10 to determine gold have been explained. The direct determination of gold by most of the analytical techniques suggested is to extend some problems becasue of the interfering matrix components at high concentrations in several real samples, therefore, an effective sample pretreatment step, such as preconcentration of the analyte and matrix isolation, are still necessary to obtain reliable results.…”

“…17 DLLME papers related to metal ions report the use of chelating ligands, ion-pair reagents and ligandless-dispersive liquid-liquid microextraction. The ion-pair-DLLME (IP-DLLME) has been employed for gold following the formation of an ion pair complex between the AuCl 4 -complex and different counter ions such as amiloride mono hydrochloride, 18 victoria blue R, 19 dicyclohexylamine, 6 and benzyldimethyltetradecyl-ammoniumchloride 20 . For many years, it has been well-known that gold is determined using a spectrophotometric method based on the reaction of AuCl 4 -with the cationic form of Rhodamine B to give a violet ion pair complex.…”