Potentialities of thermal lens spectrometry in studying peculiarities of reactions at the trace level

Проскурнин, М. А.; Chernysh, V. V.

doi:10.1007/bf02756085

Cited by 7 publications

(6 citation statements)

References 47 publications

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“…A thorough, detailed study of all the factors affecting the accuracy of thermal lensing is still needed. However, a basic verification of the accuracy and bias of TLS, CB-TLS, and TLM was done in detail in previous reports [3,12,17,28]. It was shown that investigations of the thermal-lens signal as a function of the apparent molar absorptivity, excitation-beam wavelength, etc.…”

Section: Accuracy Of Thermal-lens Measurementsmentioning

confidence: 99%

“…It has already evolved into a highly sensitive and versatile analytical technique [1,2]. A primary feature of TLS is that its overall sensitivity (subnanogram LODs down to 10 -7 absorbance units) is achieved not only through instrumentation, but also because of better conditions for photometric reactions at trace levels [3]. Other key features of TLS, locality and high spatial resolution, have led to the vigorous use of thermal-lens microscopy (TLM) as a novel detection method [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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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: Accuracy Of Thermal-lens Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

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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show abstract

“…1,2 Its high sensitivity is achieved not only through instrumentation, but also because of the reaction conditions at trace levels. 3 The locality and high spatial resolution of TLS have led to wide-scale applications of thermal-lens microscopy (TLM) as a state-of-the-art method. [4][5][6][7] TLM perfectly fits micro-totalanalytical systems (μTAS) (reactions and separations occurring at high rates in nanoscale volumes).…”

Section: Introductionmentioning

confidence: 99%

“…We have chosen Co and Fe determination because (i) the photometric methods for these metals are both sensitive and reliable; 24 (ii) they are based on the same reaction type, chelation; (iii) these methods cover all of the selected procedure types; and (iv) optimized TLS/TLM procedures have low practical LODs under batch and flow conditions. 3,4,[25][26][27][28][29][30][31][32][33][34][35][36] A total of 39 procedures (16 for Fe and 23 for Co) were considered.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Performance Parameters of Photothermal Procedures in Homogeneous and Heterogeneous Systems

et al. 2011

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The main types of analytical procedures used in thermal-lens spectroscopy and microscopy, which are based on photometric reactions in (i) aqueous solutions, (ii) organo-aqueous mixtures, (iii) polymer-containing (nonionic surfactants or polyethylene glycol) aqueous solutions, (iv) water-organic extraction systems, and (v) two-phase aqueous extraction systems, were compared from the viewpoint of both reproducibility and sensitivity. This comparison was made by examples of the determination of cobalt and iron for batch conditions, flow determination, and detection in HPLC, flow-injection analysis (FIA), and μFIA. It was revealed that for all five types, the real analytical efficiency (a decrease in the limit of detection (LOD) as compared to spectrophotometry) is primarily determined by the reaction conditions, provided that excitation of the thermal lens is the same. Aqueous solutions provide more efficient optimization of reaction conditions than do those in organo-aqueous solutions and solvent-extraction water-organic mixtures. The best results are achieved when shifting to polymer-containing aqueous solutions and two-phase aqueous extraction systems, which decreases in the LODs by a factor of 20 -100%.

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“…This strategy proved very useful for another widespread photothermal method, thermal lensing. 14 In selecting the main target application, we considered the fact that trace determination of metals, particularly iron, in seawater is one of the topical tasks of marine chemistry. Iron is a very active participant in various biological and redox processes in seawater.…”

Section: Introductionmentioning

confidence: 99%

Photothermal Deflection Determination of Iron(II) with Ferrozine with Sorption Preconcentration on Silufol Plates

Khrycheva

Nedosekin²,

Проскурнин³

et al. 2008

Appl Spectrosc

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Photothermal deflection spectroscopy was applied to the selective detection of iron(II) chelate with ferrozine by its sorption preconcentration on Silufol plates. The linearity range was 1 x 10(-11) - 6 x 10(-8) mol cm(-2) of chelate at the plate surface, which corresponded to 1 x 10(-9) -4 x 10(-6) M of chelate in solution. The limits of detection and quantification are 8 x 10(-12) and 2.5 x 10(-11) mol cm(-2) at the plate from 15 microL of test solution (0.5 nM and 1.5 nM in solution, respectively), and the absolute detection limit is 8 fmol in the whole spot applied to a plate. Characteristics and features of photothermal deflection detection are discussed.

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Potentialities of thermal lens spectrometry in studying peculiarities of reactions at the trace level

Cited by 7 publications

References 47 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

Comparison of Performance Parameters of Photothermal Procedures in Homogeneous and Heterogeneous Systems

Photothermal Deflection Determination of Iron(II) with Ferrozine with Sorption Preconcentration on Silufol Plates

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