Room temperature cloud point extraction: An application to preconcentration and spectrophotometric determination of copper(II)

Abstract

The novel cloud point extraction procedure for preconcentration of copper(II) was discovered. A simple chemical method for initiating the cloud point extraction (CPE) has been proposed. The formation of surfactant rich phase in a system containing a nonionic surfactant Triton X-100, copper(II), 6,7-dihydroxy-4-methyl-2-phenylbenzopyrilium chloride (DHMPhB) and ammonium benzoate is observed immediately upon the sulfuric acid addition into solution. Under the optimal conditions (absorption band maximum was 540 nm, concentration 1.5×10-4 mol dm-3 of DHMPhB, 1.0 vol.% of Triton X-100, 2.0 cm 3 of 0.75 mol dm-3 ammonium benzoate, and 1.0 cm 3 of 0.5 mol dm-3 sulfuric acid solution for obtaining benzoic-benzoate buffer solution with pH 4.5 and initiation immediate surfactant rich phase formation) the calibration plot for spectrophotometric determination of copper(II) was linear in the range of copper(II) concentration 0.02-0.95 µg cm −3. The limit of detection was calculated 0.006 µg cm −3. The water samples were analyzed according to a suggested procedure with satisfactory results.

A facile and sensitive coprecipitation method coupled with flame atomic absorption spectrometry for quantification of Cu(II) ions in complex matrices

“…One of these problems is the interference effect of the complicated matrix and the other is that the lower levels of trace element than the detection limit of the utilized instrument. 13 In order to eliminate these drawbacks, it is indispensable to implement a traditional separation and preconcentration method such as solid phase extraction, 14 cloud point extraction, 15 liquid-liquid extraction 16 and coprecipitation 8 before the analyses step. Among these, coprecipitation is a powerful alternative due to its low cost, simplicity and rapidity, less usage of chemical reagents and obtaining high preconcentration factors in the method.…”

Dispersive Liquid-Liquid Semi-Microextraction of Сu(II) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium Chloride for its Spectrophotometric Determination

“…Many various techniques for copper(II) preconcentration have been proposed. For example, cloud point extraction, [2][3][4] solid-phase extraction, [5][6][7] liquid extraction [8][9][10] etc., while most often copper(II) is pre-bound into ion pairs or complexes (chelates in particular) using reagents such as sodium diethyldithiocarbamate, [11][12][13] 1-(2-pyridylazo)-2-naphthol, 4,14 and dimethyl-1,10-phenanthroline (neocuproine). 15,16 It is important to note that interest in the development and modernization of various cloud point extraction and liquid extraction techniques does not disappear even today.…”