Detection of flow injection analysis with pH gradient by acousto-optic tunable filter based spectrophotometry

Pasquini, Célio; Lu, Junfeng; Tran, Chieu D.; Smirnov, S. S.

doi:10.1016/0003-2670(95)00509-9

Cited by 16 publications

(6 citation statements)

References 22 publications

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“…This IAOTF was specified to have a center wavelength of 1550 nm and a tuning range larger than 80 nm (full width at half-maximum). The rf power required is less than 150 mW, which is much lower than those used for bulk AOTFs, which is in the order of a few watts. ,− This IAOTF is fusion-spliced directly to two single-mode optical fibers (one for input and the other for output). Each fiber is terminated with an FC/SPC connector to facilitate connection with other fiber-based components.…”

Section: Methodsmentioning

confidence: 99%

“…The second fiber polarizer was connected to the output of the IAOTF to remove the transmitted light and to transmit the diffracted light. The rf driver and amplifier, similar to those used previously, ,− were used to generate, amplify, and amplitude-modulate the rf signal for the IAOTF. Depending on the type of measurements, the spectrophotometer was used as a single beam or a double beam, i.e., sample and reference beam.…”

Section: Methodsmentioning

confidence: 99%

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Determination of Monomethylhydrazine with a High-Throughput, All-Fiber Near-Infrared Spectrometer Based on an Integrated Acoustooptic Tunable Filter and an Erbium-Doped Fiber Amplifier

Tran

Gao

1997

Anal. Chem.

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A novel integrated acoustooptic tunable filter (IAOTF) has been developed. This tunable filter is based on the Bragg interactions between waveguide and surface acoustic waves. Compared to (bulk) AOTF, its advantage include all-fiber construction, smaller size, narrower spectral resolution (1.7 nm), higher diffraction efficiency (37%), and lower rf power requirement (150 mW). A relatively narrow spectral tuning range (about 80 nm) is the only drawback for this integrated tunable filter. However, this disadvantage was overcome by judiciously using the filter for measurements in which its tuning range is coincident with the light source and also with absorption bands of analytes. In fact, an all-fiber, compact, high-throughput near-infrared spectrophotometer has been successfully constructed by synergistic use of this integrated AOTF and the erbium-doped fiber amplifier (EDFA), which has been shown to provide high intensity and wide spectral band-width in the near-infrared region from 1500 to 1600 nm. This spectral region is particularly useful for the determination of samples which have O-H and/or N-H groups. The all-fiber nature, compactness, high throughput, and high sensitivity of this spectrophotometer make it particularly suitable for on-line and real-time detection of trace gases in hostile environments, including leak detection of monomethylhydrazine (at a limit of detection of 191 ppm), which is often used as the hypergolic propellant for the space shuttle thruster systems.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Determination of Monomethylhydrazine with a High-Throughput, All-Fiber Near-Infrared Spectrometer Based on an Integrated Acoustooptic Tunable Filter and an Erbium-Doped Fiber Amplifier

Tran

Gao

1997

Anal. Chem.

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“…The AOTF is an all solid state electronic dispersive device which is based on the diffraction of light in a crystal [19][20][21][22]. Light is diffracted by an acoustic wave because when an acoustic wave propagates in a transparent material, it produces a periodic modulation of the index of refraction (via the elasto-optical effect).…”

Section: Introductionmentioning

confidence: 99%

Optical Bistability in an Acousto-Optic Tunable Filter (AOTF) Operating with Short Optical Pulses

Sabóia¹,

Queiroz²,

Lima³

et al. 2012

JEMAA

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In this paper we report for the first time the presence of bistability in an acoustic-optic tunable filter (AOTF) operating with ultrashort (2 ps) optical light pulses. The results for the study of bistability has shown the dependence of the hysteresis curve with the product of the coupling constant (κ) by the length of the device (ξL) and the conversion power-coupling constant factor (G). The range of bistability varies significantly with both G and with κξL parameters. The variation of κξL directly increases the size of the range of bistability hysteresis while the increase in G causes the bistability to occur at low powers. The phenomenon of optical bistability (OB) is the object of increasing interest due to its possibilities for important device applications. A bistable device is a device with a capability to generate two different outputs for a given input and the physical requirements for this are an intensity-dependence refractive index and an optical feedback mechanism

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“…An acousto-optic tunable filter (AOTF) is an all solid state, electronic monochromator, which is based on the diffraction of light by an acoustic wave in an anisotropic crystal. − The filter can diffract incident white light at a specific wavelength when a specific radio frequency (RF) is applied into it. The wavelength of the diffracted light can be scanned over a large optical region by simply changing the frequency of the applied RF.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the tunable filter has been demonstrated to have high spectral resolution (0.82 Å at 253.4 nm) 20 and fast scanning ability (microseconds). − These features make it possible to use the AOTF to develop novel instruments that are not possible otherwise. For instance, we have recently demonstrated that a spectrophotometer based on AOTF is capable of sensitively and rapidly recording the entire absorption spectra of compounds as they elute from an HPLC column 20 or in FIA . Prior work clearly indicates that it is possible to use the AOTF-based UV−visible absorption detector as a sensitive and fast scanning detector for FIG.…”

Section: Introductionmentioning

confidence: 99%

Determination of Binding Constants by Flow Injection Gradient Technique

1998

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A new method is based on the flow injection gradient equipped with an acousto-optic tunable filter (AOTF) detector has been developed for the determination of binding constants of substrates with cyclodextrins or micelles. The concentration gradient produced by this method eliminates the need to prepare series of mixtures in which the concentrations of one of the reactants are varied. The fast scanning ability of the AOTF enables the detector to record the whole absorption spectrum of the mixture as it flows through the flow cell. Binding constants can be rapidly determined. The effectiveness of the method was evaluated by determining binding constants of inclusion complex formation between β-cyclodextrin (β-CD) and phenolphthalein and of the incorporation of organic molecules (e.g., p-toluenesulfonic acid (PTS) and benzophenone (BP)) into micelles (CTAB) under steady state condition (no flow) and compared with values determined under the flow injection gradient. The method is particularly effective for charged substrates, e.g., the binding constants obtained between PTS and CTAB and between phenolphthalein and β-CD. Neutral substrate, BP, gives relatively poor accuracy and reproducibility, and these may be due to the adsorption of the substrate onto the flow device.

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Detection of flow injection analysis with pH gradient by acousto-optic tunable filter based spectrophotometry

Cited by 16 publications

References 22 publications

Determination of Monomethylhydrazine with a High-Throughput, All-Fiber Near-Infrared Spectrometer Based on an Integrated Acoustooptic Tunable Filter and an Erbium-Doped Fiber Amplifier

Determination of Monomethylhydrazine with a High-Throughput, All-Fiber Near-Infrared Spectrometer Based on an Integrated Acoustooptic Tunable Filter and an Erbium-Doped Fiber Amplifier

Optical Bistability in an Acousto-Optic Tunable Filter (AOTF) Operating with Short Optical Pulses

Determination of Binding Constants by Flow Injection Gradient Technique

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