| dc.contributor.author | Perez Gramatges, Aurora. | en_US |
| dc.date.accessioned | 2014-10-21T12:34:01Z | |
| dc.date.available | 1999 | |
| dc.date.issued | 1999 | en_US |
| dc.identifier.other | AAINQ49263 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55642 | |
| dc.description | Several methods for the simultaneous preconcentration of selected transition metals and lanthanides by cloud point extraction (CPE) followed by their determination using neutron activation analysis (NAA) have been developed. In general, the methods involve the use of a nonionic surfactant, namely PONPE-7.5, and a chelating agent 1-(2-pyridylazo)-2-naphthol (PAN). | en_US |
| dc.description | A phase diagram of the surfactant has been constructed and the effects of different additives on the cloud point have been investigated. Other parameters that characterize the CPE, such as the ratio between the surfactant-rich and the aqueous phases and the percent of water in the surfactant- rich phase have been determined. High partition coefficients of PAN (logK d of 2.38--3.73) between the two phases have been obtained. | en_US |
| dc.description | Different factors that can influence the extraction efficiency of metals have been optimized. These factors included solution pH, ionic strength, temperature, and PAN and surfactant concentrations. The most critical parameters in the CPE have been found to be the solution pH and the concentration of the chelating agent. The extraction recoveries for most of the metal chelates are >95% under optimal conditions. A preconcentration factor of 60 has been achieved leading to low detection limits of 0.03--25 ppb. The groups of metal studied are: (i) Cd, Co, Cu, Mn, Ni and Zn; and (ii) Dy, Er, Eu, Gd, Ho, La, Lu, Pr, Sm, Tb, Tm, and Yb. | en_US |
| dc.description | Some preliminary studies have been done regarding the use of a mixture of chelating agents (TAN and PAN) in CPE. A quantitative recovery has been obtained for Hg which is not chelated efficiently by PAN only. The method has been extended to the simultaneous determination of Cd, Hg and Zn. | en_US |
| dc.description | The precision and accuracy of measurements have been evaluated using elemental comparator standards and certified reference materials, respectively. The methods have been applied to the determination of the transition metals in samples of tap and sea water. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1999. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Analytical. | en_US |
| dc.title | Simultaneous preconcentration of trace metals by cloud point extraction with 1-(2-pyridylazo)-2-naphthol and determination by neutron activation analysis. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
