Cloud point extraction and preconcentration of gold in geological matrices prior to flame atomic absorption determination

Abstract

Brilliant green was used as a complexing agent in cloud point extraction (CPE) and applied for selective preconcentration of trace amounts of gold in geological matrices. The analyte in the initial aqueous solution was acidified with hydrochloric acid (0.1 M) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with methanol and the analyte determined in the surfactant rich phase by flame atomic absorption spectrometry (FAAS). After optimization of the complexation and extraction conditions, a preconcentration factor of 31 was obtained for only 10 mL of sample. The analytical curve was linear in the range of 3-1000 ng mL −1 and the limit of detection was 1.5 ng mL −1 . The proposed method was applied to the determination of gold in geological samples.. Warsaw and Springer-Verlag Berlin Heidelberg. © Versita

Micelle mediated extraction for preconcentration of Eu(III) prior to determination by flame atomic absorption spectrometry

“…It reacts with alizarine red S, forms brown precipitate and consumes the ligand. This effect was reduced, when 0.1 M of ascorbic acid was added [17]. Ascorbic acid reduces Fe(III) to Fe(II) and prevents its reaction with ligand.…”

“…It was found that 0.6 M of HNO 3 was optimal. A volume of 200 mL of methanol (containing 0.6 mol L À1 HNO 3 ) was added to surfactantrich phase to ensure a sufficient volume of sample for aspiration [17].…”

“…Recently, CPE was reported for preconcentration of several metal ions [16][17][18][19][20][21][22][23][24][25]. It overcomes many of later mentioned limitations, In addition to, low cost, safety, and a high capacity to concentrate a wide variety of analytes [26][27][28][29][30][31][32].…”

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

“…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. Many preconcentration and separation methods have been frequently carried out using liquid-liquid [11][12][13] and liquid-solid extractions.…”

Cloud Point Extraction Spectrophotometric Method for Mutual Determination of Norfloxacin and Iron(III) in Human Serum and Drug Formulations

“…The concentration of the surfactant has an important influence in determining the efficiency of the extraction according to the cloud point extraction method, because its important stems from maximizing extraction efficiency by minimizing the phase volume ratio (V s /V a ), thus improving its perconcentration ability 26 . To illustrate this role, the effect of the triton x-114 concentration on the absorbance of the extracted Fe(III) -NOR complex was studied within the surfactant volume range of 0.1-2 mL of 10% (v/v) triton x-100 and keeping other variables constant.…”