A centrifugal stirrer for rapid mixing in square cuvets during spectrophotometric measurements

Conrad, Richard H.

doi:10.1021/ac60252a023

Cited by 11 publications

(2 citation statements)

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“…Actinometer absorbance changes were continuously monitored by the spectrophotometer [31]. Care has been taken to assess that the cuvette was sufficiently stirred [32], and that the actinometer was neither sensitive to the spectrophotometer measuring beam (laser off) nor to the NIR laser beam in the absence of UCNPs (see Supporting Information File 1).…”

Section: Resultsmentioning

confidence: 99%

A photochemical determination of luminescence efficiency of upconverting nanoparticles

Amouroux

Roux

Micheau

et al. 2019

Beilstein J. Org. Chem.

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Upconverting nanoparticles are a rising class of non-linear luminescent probes burgeoning since the beginning of the 2000’s, especially for their attractiveness in theranostics. However, the precise quantification of the light delivered remains a hot problem in order to estimate their impact on the biological medium. Sophisticated photophysical measurements under near infrared excitation have been developed only by few teams. Here, we present the first attempt towards a simple and cheap photochemical approach consisting of an actinometric characterization of the green emission of NaYF4:Yb,Er nanoparticles. Using the recently calibrated actinometer 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene operating in the green region of the visible spectra, we propose a simple photochemical experiment to get an accurate estimation of the efficiency of these green-emitting “nanolamps”. The agreement of the collected data with the previous published results validates this approach.

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Section: Resultsmentioning

confidence: 99%

A photochemical determination of luminescence efficiency of upconverting nanoparticles

Amouroux

Roux

Micheau

et al. 2019

Beilstein J. Org. Chem.

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“…ml of phenolphthalein working solution was then pipetted to the glass cell. Mixing of the two reagents was accomplished by using a small magnetic stirrer [22] inside the cell. A magnetic stirrer motor was placed underneath the sample compartment for stirring purpose.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous multiwavelength study of thereaction of phenolphthalein with sodium hydroxide

Tam

Chau

1992

Journal of Analytical Methods in Chemistry

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A photodiode array (PDA) spectrophotometer was used to study the fading reaction of phenolpthalein in dilute sodium hydroxide solution. The principal component analysis (PCA) method was employed to identify the number of light absorbing species in the kinetics system. The target factor analysis (TFA) procedure, coupled with the Broyden-Fletcher-Goldfard-Shanno (BFGS) optimization method, was applied to the observed data to deduce the rate constants and the concentration-time profile of the reaction. The internal referencing method was shown to be essential in improving the quality of data obtained by a single beam PDA spectrophotomer.

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Generation of continuous ligand–macromolecule binding isotherms. Use of exponential concentration gradients

1976

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SynopsisContinuous exponential concentration gradients, accurate, precise, and reproducible to better than I% over a t least a 10"-104 concentration range, can be easily produced. In fact, it appears that these gradients may be substantially better than this. Such gradients have been used to generate a continuous ligand binding isotherm for the system Mg++ + Eriochrome Black T over a lo6 ligand concentration range. This continuous isotherm is shown to be sufficiently precise to provide a first derivative function r(y), which is precise to 0.4%. The moments of I'(y) were calculated and found to be extremely accurate. For example, the second moment about the mean was calculated to he 3.32 and 3.30 for two different experiments compared to a theoretical value of 3.29. The general application of these techniques to generate continuous ligand binding isotherms is discussed.

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A centrifugal stirrer for rapid mixing in square cuvets during spectrophotometric measurements

Cited by 11 publications

References 0 publications

A photochemical determination of luminescence efficiency of upconverting nanoparticles

A photochemical determination of luminescence efficiency of upconverting nanoparticles

Simultaneous multiwavelength study of thereaction of phenolphthalein with sodium hydroxide

Generation of continuous ligand–macromolecule binding isotherms. Use of exponential concentration gradients

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