Optimisation of the optical scheme of a dual-beam thermal lens spectrometer using expert estimation

Проскурнин, М. А.; Kuznetsova, V. V.

doi:10.1016/s0003-2670(00)00949-1

Cited by 25 publications

(33 citation statements)

References 5 publications

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“…This means that when the probe beam diameter fits the diameter of the thermal lens, it corresponds to the experimentally optimum optical scheme. This is in good agreement with our previous data, showing that the best analytical results correspond not to the conditions with the highest slope (which should point to the lowest possible frequency), but to the conditions with the longest calibration range [14]. The latter condition is met when the diameter of the probe beam is equal to the diameter of the thermooptical element (the whole thermal lens is probed).…”

Section: Chopper Frequency and Diameter Of Thermal Lenssupporting

confidence: 92%

See 1 more Smart Citation

Thermooptical detection in microchips: From macro‐ to micro‐scale with enhanced analytical parameters

Smirnova¹,

Проскурнин²,

Bendrysheva³

et al. 2008

Electrophoresis

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In this paper, we compared the methods of photothermal spectroscopy used in different spatial scales, namely thermal-lens spectrometry (TLS) and thermal-lens microscopy (TLM) to enhance the performance parameters in analytical procedures. All of the experimental results were confirmed by theoretical calculation. It was proven that the design for both TLM and TLS, despite a different scale for the effect, is governed by the same signal-generating and probing conditions (probe beam diameter at the sample should be equal to the diameter of the blooming thermal lens), and almost does not depend on the nature of the solvent. Theoretical and experimental instrumental error curves for thermal lensing were coincident. TLM obeys the same law of instrumental error as TLS and shows better repeatability for the same levels of thermal-lens signals or absorbances. TLS is more advantageous for studying low concentrations in bulk, while TLM shows much lower absolute LODs due to better repeatability for low amounts. The behavior of the thermal-lens signal with different flow rates was studied and optimum conditions, with the minimum contribution to total error, were found. These conditions are reproducible, are in agreement with the existing theory of the thermal response in thermal lensing, and do not significantly affect the design of the optimum scheme for setups. TLM showed low LODs in solvent extraction (down to 10(-8) M) and electrokinetic separation (10(-7) M), which were shown to be governed by discussed instrumental regularities, instead of by microchemistry.

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Section: Chopper Frequency and Diameter Of Thermal Lenssupporting

confidence: 92%

“…Thermal-lens spectrometers with already optimized parameters [13][14][15] and a desktop thermal-lens microscope with default manufacturer settings [5] were used. The optimization of the latter is not included in this work.…”

Section: Equipmentmentioning

confidence: 99%

Thermooptical detection in microchips: From macro‐ to micro‐scale with enhanced analytical parameters

Smirnova¹,

Проскурнин²,

Bendrysheva³

et al. 2008

Electrophoresis

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“…The selection of the parameters of the instrument (linear dynamic range, opticalscheme design, instrumental sensitivity, etc.) are discussed elsewhere [11,12].…”

Section: Reagentsmentioning

confidence: 99%

“…To synchronize the detection system with the working mode of the shutter monitored by the computer via the ADC-DAC board (8), part of the excitation beam is directed by a plate (10) to a synchronizing photodiode (11). The output is coupled to a synchronizing unit (12). The excitation beam focused by a lens (13) passes through a thick plate (14), which is used for fine justification of the propagation of beams in the cell, and a Glan prism (15) and enters the cell (16).…”

Section: Reagentsmentioning

confidence: 99%

“…where d σ0 is the diameter of the (radially symmetric) probe beam at a far-field detector plane in the absence of a thermal lens; d σx and d σy are the horizontal and vertical diameters of the probe beam for a steady-state thermal lens; and d′ σx and d′ σy are the horizontal and vertical diameters of the thermal lens; and k i are weight coefficients [12].The values of d σ0 , d σx , d σy , d′ σx , and d′ σy were measured in a far-field plane (5 m) according to the recommendations of ISO 11146 standard procedure [17].…”

Section: Data Treatmentmentioning

confidence: 99%

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Optical photothermal detection in HPLC

et al. 2003

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A mode-mismatched parallel dual-beam thermal lens spectrometer with a far-field single-channel detector system was used as a detector in HPLC. An expert estimation of the measurement results was applied to optimize the optical-scheme configuration of the spectrometer to achieve the longest linear calibration range and highest repeatability under chromatographic flow conditions. Chelates with 4-(2-pyridylazo)resorcinol were separated and determined with the limits of detection of n x 10(-8)- n x 10(-7) mol L(-1); the relative standard deviation of measurements was 46%. Xylenol Orange, 4-(2-thiazolylazo)resorcinol, and dithizone were studied as post-column reagents in thermal lens detection in ion chromatography. The limits of detection were n x 10(-8)- n x 10(-7) mol L(-1); the linear calibration ranges were about three orders; the relative standard deviation of measurements was 3-7%. A combined photothermal-refractometric detector for HPLC based on a polarization interferometer is proposed. Metal complexes as 4-(pyridylazo)resorcinol chelates (limits of detection of n x 10(-8)- n x 10(-7) mol L(-1)) and sugars (limits of detection of 10-20 ng L(-1)) were investigated as model substances. Obtained results were compared with results for traditional detectors, which show that photothermal detection has higher sensitivity than photometric and other absorption detectors.

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Ultrasensitive label‐free photothermal imaging, spectral identification, and quantification of cytochrome c in mitochondria, live cells, and solutions

Brusnichkin

Nedosekin

Galanzha

et al. 2010

Journal of Biophotonics

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Light-absorbing endogenous cellular proteins, in particular cytochrome c, are used as intrinsic biomarkers for studies of cell biology and environment impacts. To sense cytochrome c against real biological backgrounds, we combined photothermal (PT) thermal-lens single channel schematic in a back-synchronized measurement mode and a multiplex thermal-lens schematic in a transient high resolution (ca. 350 nm) imaging mode. These multifunctional PT techniques using continuous-wave (cw) Ar+ laser and a nanosecond pulsed optical parametric oscillator in the visible range demonstrated the capability for label-free spectral identification and quantification of trace amounts of cytochrome c in a single mitochondrion alone or within a single live cell. PT imaging data were verified in parallel by molecular targeting and fluorescent imaging of cellular cytochrome c. The detection limit of cytochrome c in a cw mode was 5 × 10−9 mol/L (80 attomols in the signal-generation zone); that is ca. 103 lower than conventional absorption spectroscopy. Pulsed fast PT microscopy provided the detection limit for cytochrome c at the level of 13 zmol (13 × 10−21 mol) in the ultra-small irradiated volumes limited by optical diffraction effects. For the first time, we demonstrate a combination of high resolution PT imaging with PT spectral identification and ultrasensitive quantitative PT characterization of cytochrome c within individual mitochondria in single live cells. A potential of far-field PT microscopy to sub-zeptomol detection thresholds, resolution beyond diffraction limit, PT Raman spectroscopy, and 3D imaging are further highlighted.

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Optimisation of the optical scheme of a dual-beam thermal lens spectrometer using expert estimation

Cited by 25 publications

References 5 publications

Thermooptical detection in microchips: From macro‐ to micro‐scale with enhanced analytical parameters

Thermooptical detection in microchips: From macro‐ to micro‐scale with enhanced analytical parameters

Optical photothermal detection in HPLC

Ultrasensitive label‐free photothermal imaging, spectral identification, and quantification of cytochrome c in mitochondria, live cells, and solutions

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