Sensitive and Simple Cloud-point Preconcentration Atomic Absorption Spectrometry: Application to the Determination of Cobalt in Urine Samples

Abstract

A new approach for developing a cloud-point extraction-flame atomic absorption spectrometric method has been described and used for the determination of cobalt. In this approach, water was removed from the final diluted surfactant rich phase obtained in cloud-point extraction procedure. The results indicated that removing water from this phase increased the enhancement factor by 4-fold. 1-(2-Pyridylazo)-2-naphthol (PAN) and octylphenoxypolyethoxyethanol (Triton X-114) were used as a hydrophobic ligand and a nonionic surfactant, respectively. The chemical variables affecting the preconcentration step were optimized. The effect of the water concentration in the final diluted methanolic surfactant solution on the analytical signal was investigated. The results showed that the analytical signal decreased by 30% and 52% in 15% and 25% water concentrations in methanol, respectively. An enhancement factor of 115 was obtained for cobalt extracted from only 10 ml of a sample. The detection limit obtained under the optimal condition was 0.38 µg l -1 . The proposed procedure was applied to the determination of cobalt in urine samples.

Synthesis of Bis(amino alcohol)oxalamides and Their Usage for the Preconcentration of Trace Metals by Cloud Point Extraction

“…They include functional groups that can form strong complexes with metals. In recent literature, some ligands, such as ammonium pyrrolidinedithiocarbamate (APDC), 33 1-(2-pyridylazo)-2-naphthol (PAN), 34 1-(2-thiazolyazo)-2-naphthol (TAN), 35 O,Odiethyldithiophosphate (DDTP), 36 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA), 37 diethyldithiocarbamate (DDTC), 38 8-hydroxyquinoline (oxine), 39 dithizone, 40 and 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol (Br-PADAP) 41 have been especially used for the preconcentration of different metals. The complexes form with ligands in individual pH values for one or two element with their active centers.…”

Use of Escherichia coli Immobilized on Amberlite XAD-4 as a Solid-Phase Extractor for Metal Preconcentration and Determination by Atomic Absorption Spectrometry

“…Various separation and preconcentration techniques have been used for trace metals, such as solvent extraction, [1][2][3] coprecipitation, [4][5][6] electrodeposition, 7 ion-exchange, [8][9][10] cloud point extraction technique 11 and solid-phase extraction 12 (SPE), adsorption on activated carbon, 13 on dithixone-anchored poly(EGDMA-HEMA) microbeads, 14 on Amberlite resins 15 and on sepiolite. 16 The preconcentration procedures employing a solid phase and applied to atomic spectrometry present some advantageous characteristics, such as simplicity, column applicability and a higher preconcentration factor.…”

Ion-Pair Formation of a Copper(II)-Ammine Complex with an Anionic Surfactant and the Recovery of Copper(II) from Ammonia Medium by the Surfactant-Gel Extraction Method

“…[4][5][6][7][8][9][10] Sodium dodecylsulfate (SDS), which has low toxicity and is easily biodegraded, was used as the extraction medium. The purpose of this study is the extraction of a copper(II) ammine-complex with SDS after ion-pair formation.…”