Spectrochemical investigations of fluorescence quenching agents. Part 5. Effect of surfactants of the ability of nitromethane to selectively quench fluorescence emission of alternant PAHs.
Applicability of the nitromethane selective quenching rule for discriminating between alternant vs. nonalternant polycyclic aromatic hydrocarbons (PAHs) is examined for 18 representative PAH solutes dissolved in micellar cetyltrimethylammonium chloride (CTACl), micellar dodecyltrimethylammonium bromide (DTAB), micellar Brij-35 and micellar sodium octanoate (SO) solvent media. Experimental results show that nitromethane quenched fluorescence emission of only the 10 alternant PAHs in the two cationic (CTACl and DTAB) and nonionic Brij-35 surfactant solvent media as expected. Emission intensities of nonalternant PAHs, except for the few exceptions noted previously, were unaffected by nitromethane addition. Unexpected quenching behavior was observed, however, in the case of nonalternant PAHs dissolved in micellar sodium octanoate solvent media. Nitromethane quenched fluorescence emission of all nonalternant PAHs studied in the SO solvent media, which is contrary to the selective quenching rule.
Pandey
S
S
Department of Chemistry, University of North Texas, Denton 76203-0068, USA.
Fletcher
K A
KA
Powell
J R
JR
McHale
M E
ME
Kauppila
A S
AS
Acree
W E
WE
Fetzer
J C
JC
Dai
W
W
Harvey
R G
RG
D005456:Fluorescent Dyes; D008697:Methane / Q000031:analogs & derivatives; D008823:Micelles; D015394:Molecular Structure; D009595:Nitroparaffins; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013501:Surface-Active Agents
D005456:Fluorescent Dyes; D008823:Micelles; D009595:Nitroparaffins; D011084:Polycyclic Aromatic Hydrocarbons; D013501:Surface-Active Agents; D008697:Methane; C008640:nitromethane