Fluorescence quenching of tertiary amines by halocarbons

Alford, Peter C.; Cureton, C.G.; Lampert, R.A.; Phillips, David

doi:10.1016/0301-0104(83)85054-x

Cited by 12 publications

(17 citation statements)

References 29 publications

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“…The precision of the halothane assay is again the same as that of the halothane evaporator and may become better with a more precise vaporizer. DISCUSSION Quenching of polyaromatics by alkyl or aryl halides has been studied in several cases (21)(22)(23)(24)(25)(26)(27)(28)(29), but not with halothane. In fact it has been stated (30) that this anesthetic does not interfere in the fluorometric oxygen sensor.…”

Section: Indicators a Variety Of Polycyclic Aromatic Hydrocarbonsmentioning

confidence: 99%

Fiber optical fluorosensor for determination of halothane and or oxygen

Wolfbeis¹,

Posch²,

Kroneis³

1985

Anal. Chem.

130

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A flber optical fluoroescence sensor for measurlng concentrations of the wldeiy used lnhalatlon narcotic halothane In the presence of varying concentratlons of oxygen is presented. I t Is based on dynamlc fluorescence quenching and consists of a highly halothane-sensltive indlcator layer exposed to the sample. Interferences by molecular oxygen are taken Into account by a second, polytetrafluoroethylene-covered fluorescent indlcator layer highly sensltlve toward oxygen. Haiothane concentrations can be calculated wlth the help of an extended Stern-Volmer relation (eq 10). The two-sensor technlque presented here allows the determination of halothane, or oxygen, or both wlth a preclslon of 1 5 % for halothane and 13.5% for oxygen In the concentration range encountered in practlce. The probe Is practlcally speclflc for the two anaiytes, since other gases present in inhalatlon gases or blood including carbon monoxlde, dlnltrogen monoxlde, or fluorans do not interfere. The method is thought to be applicable to various other quenching analyte couples as well.Halothane (2-bromo-2-chloro-l,l,l-trifluoroethane) is the inhalation narcotic most frequently used in anesthetics (1). Numerous methods for its determination in breath gas and blood have been described. They are based on quite different analytical techniques such as gas chromatography (2,3), UV (4, 5 ) , mass (6, 71, or NMR spectrometry (81, and surface plasmon resonance (9). A commercially available monitor for anesthetic gases ("EMMA") is based on the absorption of, e.g., halothane, by a thin oil film. The physical parameter measured in this case is the mass of the film which is monitored with a piezoelectric crystal (10). The Datex anesthetic agent monitor measures halothane (or other anesthetic gases) in air via their characteristic IR absorption.Unfortunately, all of these methods either do not allow continuous determination of halothane or are not suitable for use in probes or catheters. We have taken advantage of the observation that halothane is able to quench the fluorescence of polycyclic aromatic hydrocarbons and have devised a fiber-optical sensor suitable for ita continuous monitoring. Since all indicators were also quenched by molecular oxygen-a process that is frequently observed and can be used for sensing oxygen (1 l-l6)-the Stern-Volmer equation has to be modified to take into account multiple quenching. Fluorescence quenching of oxygen-sensitive indicators by halothane has already been noticed (16), a fact that makes all oxygen sensors based on dynamic fluorescence quenching halothane-sensitive and can lead to considerable bias in clinical routine.We report here on the first sensor that is able to probe both oxygen and halothane with practically no mutual interference. Its fiber optical design can be quite similar to that reported by Peterson et al. (16), except that two fibers are required and the mathematics is slightly more complicated. THEORY Halothane in Air. Dynamic fluorescence quenching is known to obey the Stern-Volmer equation (eq l), whi...

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Section: Indicators a Variety Of Polycyclic Aromatic Hydrocarbonsmentioning

confidence: 99%

Fiber optical fluorosensor for determination of halothane and or oxygen

Wolfbeis¹,

Posch²,

Kroneis³

1985

Anal. Chem.

130

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“…[6][7][8][9] In order to achieve light energy utilization in molecular assemblies such as micelles, vesicles, and reverse micelles, it is necessary to control the net charge separation efficiency to minimize the back electron transfer. [11][12][13][14][15][16][17][18] Halogenated compounds have been used as electron acceptors or excited state quenchers in flash photolysis studies of aromatic compounds such as pyrene, 19 N,N,N′,N′-Tetramethylbenzidine (TMB), 20,21 and N,N,N′,N′-tetramethylphenylenediamine (TMPD). It has been shown that these structural factors are controllable by changing the counterion, surfactant headgroup, and alkyl chain length of the photoionizable donors and adding salts or electron acceptors.…”

Section: Introductionmentioning

confidence: 99%

Photoionization of (p-Alkylphenyl)triphenylporphyrins in Neutral and Positively and Negatively Charged Vesicles: Effects of Alkyl Chain Length and Addition of Chloroalkanes

Sung-Suh

Kevan

1997

J. Phys. Chem. A

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The photoionization of (p-alkylphenyl)triphenylporphyrins (C n PtPP) in cationic dioctadecyldimethylammonium chloride (DODAC), neutral dipalmitoylphosphatidylcholine (DPPC), and anionic dihexadecyl phosphate (DHP) frozen vesicles has been studied by electron spin resonance (ESR) with visible light irradiation at 77 K with and without addition of chloroalkanes (CCl 4 , CHCl 3 , CH 2 Cl 2 , or CH 3 CH 2 CH 2 Cl) as electron acceptors. C n PtPP (n ) 3, 6, 9, and 12) were synthesized and used to study the effects of alkyl chain length. The photoionization efficiency was found to decrease with increasing alkyl chain length of C n PtPP. The relative photoyield of the porphyrin cation radical (C n PtPP + ) measured by ESR decreased in the order DODAC > DPPC > DHP. The addition of CCl 4 , CHCl 3 , CH 2 Cl 2 , or CH 3 CH 2 CH 2 Cl into C 9 PtPP/DHP vesicles enhanced the C 9 PtPP + radical photoyield. All four chloroalkanes acted as better electron acceptors in competition with water at the vesicle interface. The results are discussed in terms of the alkyl chain length of C n PtPP, the vesicle surface charge, and the effects of chloroalkanes as electron acceptors. IntroductionPhotochemical solar energy conversion is a vitally important and active research area because visible light is an inexpensive and ever renewable source of energy. 1-3 Photoinduced charge separation of photoionizable molecules in heterogeneous systems such as vesicles, micelles, and porous inorganic materials has been studied with a goal to design artificial photoredox systems for solar energy conversion and storage. 3-18 So, it is important to study the photoionization of molecules photoionized with visible light. For this purpose, porphyrin derivatives have been used as photosensitive electron donors due to their structural and functional similarities to chlorophylls and their absorption of visible light. [6][7][8][9] In order to achieve light energy utilization in molecular assemblies such as micelles, vesicles, and reverse micelles, it is necessary to control the net charge separation efficiency to minimize the back electron transfer. [3][4][5][8][9][10][11][12][13][14][15][16][17][18] This net charge separation efficiency is strongly affected by structural factors such as the surface charge distribution of the vesicles, the degree of interaction between water and the surface of the molecular assembly, and the location of the electron donors and acceptors. It has been shown that these structural factors are controllable by changing the counterion, surfactant headgroup, and alkyl chain length of the photoionizable donors and adding salts or electron acceptors. The yield of photoinduced cation radical or converted paramagnetic products can be measured in the frozen state with electron spin resonance (ESR). In previous work, the location of photoionizable molecules such as alkylviologen, 11 alkylphenothiazine, 13-16 or (p-alkoxyphenyl)triphenylporphyrin 17,18 within vesicles or micelles was controlled by varying the pendant alkyl chain length. By alte...

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“…I), along with the well-known photophysical (1,(26)(27)(28)(29)(30) and photochemical (7,(33)(34)(35) results in the aromatic electron donor -CC14 system, strongly suggest the following primary photophysical and photochemical processes of the NEC molecule in the presence of CCI,: [2] 'NEC* -+ NEC + hv,…”

Section: Resultsmentioning

confidence: 90%

“…In an acid reaction medium, reaction [13] seems to be the main source of radical P. Comparatively low yield of carbazole reaction medium, intermediates a and yi can also be formed by reactions [26] and [27].…”

Section: Reactions Of Radical Pmentioning

confidence: 99%

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One-electron photooxidation of N-ethylcarbazole in the presence of carbon tetrachloride. Products and mechanism of the photochemical reaction

Zelent¹,

Durocher²

1985

Can. J. Chem.

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This paper is dedicated to Professor Camille Sandorfjr on the occasion of his 65th birthdayBOGUMIL ZELENT and GILLES DUROCHER. Can. J. Chem. 63, 1654 (1985.The mechanism of the photodecomposition of N-ethylcarbazole (NEC) in the presence of carbon tetrachloride has been discussed on the basis of the photoproducts identified. The photodissociation of the N-ethyl bond and the electron transfer in the transiently formed ex-CT complex, '(NEC"..-CCI.,'-)*, have been proposed as the primary photochemical processes involved irr the singlet excited NEC molecule. The latter, treated as the main process, leads to the radical cation of NEC, chloride ion, and trichloromethyl radical in the solvent cage, [NEC"CI-CCI,]. The other reactions in the system studied are analysed following the decomposition of NEC" in the presence of C1-and CCI,, which can occur by the N-ethyl group and (or) by the aromatic ring. The formation of intermediate products such as in the solvent cage gives rise to secondary photochemical reactions in the system studied. The polarity and chemical activity of the reaction media used strongly influence the nature of the secondary photochemical transformations both in and outside the solvent cage. The formation mechanism of the photochemical reaction products in CCI, when ammonia was used, after and during irradiation, has been explained mainly by the transformations of the radical a, and cation a~. as well as by the carbazyl radical P, which is also formed in the reaction medium. On the other hand, reaction of the cation y: explains the formation of the photoproducts in the irradiated solution of NEC with CClj in ethanol. These photochemical results have been compared to the photochemical reactions involved in the carbazole-CC14 system. BOGUMIL ZELENT et GILLES DUROCHER. Can. J. Chem. 63, 1654 (1985).Le mCcanisme de la photodCcomposition du Cthyl-N-carbazole (NEC) en prksence de tktrachlorure de carbone (CCI,) est analysC suite ['identification des photoproduits obtenus. La photodissociation du lien N-Cthyl ainsi que le transfert Clectronique dans le complexe excitC de transfer de charge '(NEC''...CCI,'-)* peuvent Ctre la cause de l'acte photochimique primaire suite a I'excitation du NEC dans son Ctat premier singulet. Le phototransfert Clectronique conduit I'apparition du radical cation du NEC, a I'anion chlorure et au radical trichloromCthyl dans la cage du solvant, [NECt'CI-CCI,]. La dCcomposition du radical cation en prksence de C 1 et de CCI, s'effectue par I'attaque du groupe N-Cthyl ou par le noyau aromatique. Les produits intermkdiaires suivants: dans la cage du solvant donnent lieu a ]'ensemble des rCactions photochimiques secondaires. La polarit6 ainsi que I'activitC chimique du milieu rkactionnel influencent fortement la nature des transformations photochimiques secondaires dans la cage du solvant et en dehors de celle-ci. Le mecanisme de formation des produits photochimiques dans le CCI, lorsque I'ammoniaque est ajoutC au cours et aprks I'irradiation s'explique principalement par la transformat...

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Fluorescence quenching of tertiary amines by halocarbons

Cited by 12 publications

References 29 publications

Fiber optical fluorosensor for determination of halothane and or oxygen

Fiber optical fluorosensor for determination of halothane and or oxygen

Photoionization of (p-Alkylphenyl)triphenylporphyrins in Neutral and Positively and Negatively Charged Vesicles: Effects of Alkyl Chain Length and Addition of Chloroalkanes

One-electron photooxidation of N-ethylcarbazole in the presence of carbon tetrachloride. Products and mechanism of the photochemical reaction

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