This study investigates the influence of ionic strength on the binding
constant (KDOC) between benzo(h)quinoline (BHQ) and LHA by using
fluorescence quenching method. Being a basic polycyclic aromatic
hydrocarbon, BHQ is the dominated solute as the solution¡¦s pH value is
higher than BHQ¡¦s pKb. In contrast, BHQ+ is the major species as the
solution¡¦s pH value is lower than BHQ¡¦s pKb. In a salty neutral or basic
LHA solution, the cation will bind with the acidic functional groups of
LHA, then the conformation of LHA would be coiled up to be small in
size. Due to that, leading to the decrease of the corresponding BHQ¡¦s
KDOC. Furthermore, the charge density of cation is an important factor in
control of the variation of BHQ¡¦s KDOC. The lower charge density of
cation is, the less BHQ¡¦s KDOC varied. Besides, SO4
2- may suppress the
binding affinity between Na+ and the acidic function groups of LHA, so
that lower variation of BHQ¡¦s KDOC was observed than that of Cl- in a
Na+ contained LHA solution. In an acidic solution, cation will also bind
with the acidic functional groups of LHA, leading to the decrease of the
binding sites of BHQ+ on LHA and the corresponding BHQ+¡¦s KDOC.
Besides, Mg2+ could provide more binding sites for the acidic functional
groups of LHA than Na+, so that the variation of BHQ+¡¦s KDOC with
Mg2+ addition is higher than that with Na+ addition.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0829107-122607 |
| Date | 29 August 2007 |
| Creators | gao, shu-min |
| Contributors | Chi-Ying Hsieh, Shih-Hsiung Chen, Chon-Lin Lee, Wei-Hsien Wang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0829107-122607 |
| Rights | withheld, Copyright information available at source archive |
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