Cloud point extraction preconcentration for the determination of trace copper in water sample spectrophotometry

Abstract：A new method for the determination of trace copper in water sample by spectrophotometry with cloud point extraction is put forward.The method is based on the complexation of Cu (Ⅱ) with 8-hydroxyquinoline (8-Ox) which form an hydrophobic complex and subsequently enter surfactant-rich phase at pH 7.0.Thus, the separation of Cu (Ⅱ) and the matrix could be realized.The concentrated analyte was determined by spectrophotometric methods after proper disposal.At NH3-NH4Cl buffer solution, the maximum wavelength of absorption of Cu (Ⅱ) -8-Ox complex is 395 nm, ε=7.69×105L·mol-1·cm-1.The limit of detection (LOD) for Cu (Ⅱ) is 1.28 μg L-1 and the relative standard deviation (RSD) for six replicate measurements of 0.1μgmL-1 Cu (Ⅱ) is 4.3%.The method is applied for the determination of trace copper in water sample successfully and with satisfactory results.

Keyword：Cu (Ⅱ) ;8-hydroxyquinoline;water sample;cloud point extraction;spectrophotometry;