A micro-hole potentiostatic oxygen sensor for oceanic CTDs

Atkinson, Marlin J.; Thomas, Florence I. M.; Larson, Nordeen; Terrill, Eric; Morita, Kenichi; Liu, C.C.

doi:10.1016/0967-0637(95)00019-3

Cited by 49 publications

(20 citation statements)

References 9 publications

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Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material

Amao¹,

Okura

2000

Analusis

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Recent years have seen a growing interest in optical sensors based on oxygen-induced or temperature-induced changes in the luminescence intensity of organic dyes [1][2][3][4]. Probes available for optical temperature sensor are fluorescent, thermal-quenchable and non oxygen-quenchable organic and inorganic dyes, such as coumarin, perylene, pyronin and rare earth metal compounds [5][6][7]. One of the candidate probes available for the optical temperature sensor is fullerene. Fullerenes possess useful electronic and photochemical properties [8][9][10]. As the fluorescence lifetime of fullerene C 60 is estimated to be 1.1 ns, the fluorescence of C 60 is not quenched by oxygen [11]. Thus, the fluorescence intensity of C 60 is changed by temperature changes. Thus, fullerene is attractive compound for optical temperature sensing based on the fluorescence intensity change thermally.In this letter we describe a new optical temperature sensing material, fullerene C 60 immobilized in polymethylmethacrylate (PMMA) film, and its temperature sensing properties. ExperimentalC 60 was obtained from Tokyo Kasei Inc. and was purified by recrystalization with toluene-benzene. PMMA (average M.W. 280 000, GPC grade) was purchased from Aldrich. The C 60 immobilized in PMMA film was formed by casting a mixture of 20 wt. % PMMA and C 60 in toluene onto 1.4 × 5.0 cm non-luminescent glass slides. The C 60 concentration in the film was approximately 1.0 × 10 -3 mol dm -3 . The films were dried at room temperature and stored in the dark prior to use. The thickness of the films was determined by the use of a micron-sensitive calliper. The thickness of the prepared film was c.a. 50 µm. The fluorescence spectrum of the C 60 film was measured using a Shimadzu RF-5300PC spectrofluorophotometer with a 150 W Xenon lamp as the excitation light source. The excitation and emission bandpasses were 10 and 5.0 nm, respectively. The sample film was mounted at a 45º angle to minimize light scattering from the sample and substrate. The temperature (260-373 K) was controlled using an Oxford Instrument Optistat-DN cryostat system. All the experiments were carried out under ambient condition.Theory of optical temperature sensing based on the fluorescence intensity change of C 60 film is as follows. The quantum yield (Φ) in the absence of quencher is given bywhere I a is the absorption intensity. k L and k D are the rate constants for the fluorescence and the radiationless deactivation, respectively. The deactivation term, k D is decomposed into a temperature-independent part k 0 and a temperature-dependent part k 1 that is related to thermally activated intersystem crossing. The k 1 can be assumed to have an Arrhenius form as follows:where A, E and R are a constant, the Arrhenius activation energy and the universal gas constant, respectively. The eq.(1) is re-written by the eq. (2) of the radiationless deactivation rate: Keyword. Optical temperature sensing -fullerene -fluorescence quenching -Arrhenius activation energy -polymer film.

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Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material

Amao¹,

Okura

2000

Analusis

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“…Oxygen electrodes (polarographic or Clark-type) are much simpler and are widely used for continuous monitoring (e.g., Atkinson et al, 1995). However, the sensor is not always stable, and instrumental drift is inevitable.…”

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Use of an optical oxygen sensor to measure dissolved oxygen in seawater

et al. 2006

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“…The decay of the photoexcited triplet state of PtOEP under oxygen saturated condition was faster than that under argon saturated condition, indicates the effective quenching of the excited triplet state of PtOEP by oxygen. (1) and (2). The decays consisted of two components (shorter and longer lifetimes) under various oxygen concentration conditions.…”

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Optical oxygen sensing based on triplet-triplet decay of platinum octaethylporphyrin-polystyrene film using time-resolved spectroscopy by laser flash photolysis

Amao¹,

Asai²,

Okura

1999

Analusis

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Determination of oxygen concentration is important in various fields of chemical, clinical analysis and environmental monitoring [1,2]. Recently, much attention has been paid to optical sensors based on the luminescence quenching of the indicator [3] such as polycyclic aromatic hydrocarbons [4][5][6], metalloporphyrins [7][8][9] and transition metal complexes [10][11][12], by oxygen, because of their high sensitivity and specificity. Many studies on optical sensing have explored the luminescence intensity change by oxygen. Although intensity measurements are simple, the observed intensity depends on the thickness of the sensing film, scattering light from background or the concentration of dye in the film. We reported the optical oxygen sensing system using luminescence intensity change of platinum octaethylporphyrin-polystyrene (PtOEP-PS) film by oxygen [8]. However, the oxygen sensing mechanism of PtOEP-PS film has not been clarified. On the other hand, lifetime measurements are concerned only with the rate of decrease of the light emission following a flash of excitation light and do not depend on the absolute intensity of the emitted light. The concept of using lifetime measurement of photoexcited triplet state of dye has proven to be attractive for optical oxygen sensing. It has important advantages for certain applications compared to the steady state luminescence quenching based methods [13]. As reported previously, the optical oxygen sensing system based on triplet-triplet absorption quenching of zinc porphyrin-polymer film by oxygen using timeresolved spectroscopy by laser flash photolysis has been developed [14]. By using this method, the oxygen sensing mechanism of PtOEP-PS will be clarified.In this letter, we describe the properties of optical oxygen sensing based on triplet-triplet absorption decay of PtOEP-PS film by oxygen using a time-resolved spectroscopy by laser flash photolysis. ExperimentalPtOEP (obtained from Porphyrin Products, Logan, UT, USA)-PS (average M.W. 280 000, GPC grade obtained from Aldrich, Milwaukee, WI) films were formed by casting mixture of 30-wt % PS in toluene and PtOEP onto non-luminescence glass slides. The concentration of PtOEP in PS was approximately 3.0 × 10 -5 mol dm -3 . The films were dried at room temperature and stored in dark prior to use. The PtOEP-PS film has a good photostability under laser irradiation. Laser flash photolysis was carried out using Nd-YAG OPO laser (Spectra Physics, pulse width 10 ns) at room temperature. The excitation wavelength was 535 nm, which is attributed to Q-band of PtOEP. The experimental setup for optical oxygen sensing using laser flash photolysis are reported previously [14]. The decay curves of photoexcited triplet state of PtOEP-PS film were obtained by averaging 256 single shots using a storage oscilloscope (SONYTektronix TDS360). Decay curves were analyzed without deconvolution by fitting with the following equation: 885Optical oxygen sensing based on triplet-triplet decay of platinum octaethylporphyrin-polystyrene film usin...

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A micro-hole potentiostatic oxygen sensor for oceanic CTDs

Cited by 49 publications

References 9 publications

Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material

Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material

Use of an optical oxygen sensor to measure dissolved oxygen in seawater

Optical oxygen sensing based on triplet-triplet decay of platinum octaethylporphyrin-polystyrene film using time-resolved spectroscopy by laser flash photolysis

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A micro-hole potentiostatic oxygen sensor for oceanic CTDs

Cited by 49 publications

References 9 publications

Fullerene C60 immobilized in polymethylmethacrylate film as an optical temperature sensing material

Fullerene C60 immobilized in polymethylmethacrylate film as an optical temperature sensing material

Use of an optical oxygen sensor to measure dissolved oxygen in seawater

Optical oxygen sensing based on triplet-triplet decay of platinum octaethylporphyrin-polystyrene film using time-resolved spectroscopy by laser flash photolysis

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Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material

Fullerene C₆₀ immobilized in polymethylmethacrylate film as an optical temperature sensing material