POLYMER-MEDIATED EXTRACTION FOR MICROPLATE READER SPECTROPHOTOMETRIC DETERMINATION OF PPB-LEVEL COPPER(II) ION IN WATER

Citation
T. Saitoh et al., POLYMER-MEDIATED EXTRACTION FOR MICROPLATE READER SPECTROPHOTOMETRIC DETERMINATION OF PPB-LEVEL COPPER(II) ION IN WATER, Analytical sciences, 14(5), 1998, pp. 929-933
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Analytical
Journal title
ISSN journal
0910-6340
Volume
14
Issue
5
Year of publication
1998
Pages
929 - 933
Database
ISI
SICI code
0910-6340(1998)14:5<929:PEFMRS>2.0.ZU;2-I
Abstract
A negatively charged metal chelate, bis(bathocuproinedisulfonic acid)- copper(I), was formed and stably solubilized in an aqueous solution of a water-soluble polymer, poly(N-isopropylacrylamide) (PNIPAAm), at ro om temperature. When the solution was warmed at 40 degrees C, PNIPAAm became water-insoluble. It then formed a gum-like aggregate (polymer p hase) having a very small volume. The chelate was difficult to be extr acted to the polymer phase in the absence of counter ions, but was eff iciently incorporated when appropriate amounts of quaternary ammonium ion are present as the counter ions. The recovery of the chelate incre ased with increasing the concentration or the hydrophobic properties o f the counter ions, indicating the ion-pair extraction of the charged chelate into the polymer phase. In the presence of 1 mM dodecyltrimeth ylammonium chloride, the recovery of the chelate was quantitative. Aft er the polymer phase was dissolved by 1-propanol in the hole of a 96-h ole microplate, the absorbance at 450 nm of copper(I) chelate was meas ured. A slightly curved calibration was obtained in the copper(II) con centration range from 5x10(-9) M to 5x10(-7) M. The standard deviation was 6% (n=5) for 5x10(-8) M copper(II) ions.