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Fibre accessory for the FluoTime 100 The FluoTime 100 can optionally be equipped with a fibre probe for excitation and emission collection. For this purpose the usual sample chamber is modified to hold the fibre probe. This special configuration gives even more freedom and flexibility to investigate different kinds of samples.
The following measurement data were aquired with a FluoTime 100 equipped with a fibre probe. This special all silica light guide has a reported spectral range of 250 nm - ; 2000 nm and consists of four multimode fibres: one excitation fibre with 100 µm diameter and three detection fibres of 400 µm diameter. The probe has a light tight jacket and its tip is incorporated in a stainless steel cannula. Other types of probes can also be used upon request. a) Excitation efficiency of the excitation fibre The excitation efficency of the fibre is measured as the percentage of laser power that comes through the fibre with respect to the laser power that is available with the common setup using a cuvette holder. Setting this value to 100%, the follwing excitation efficiencies could be measured:
As obvious from the data, the excitation efficiency in the red is excellent, whereas in the blue it is lower than in the cuvette holder based setup, but still large enough to allow for a decent lifetime measurement. b) Collection efficiency of the emission fibre To determine the collection efficiency of the emission fibres, the fluorescence lifetime of well known samples (Oxazin 4 and Coumarin 6 dissolved in ethanol) were measured with the cuvette holder based setup and again with the fibre probe without changing the other measurement conditions. The amount of collected photons below the fluorescence decay curve is taken as a measure of the collection efficiency, setting the result from the measurement with the cuvette holder based setup to 100%.
The data clearly shows that measuements with the probe immersed into the cuvette gives a higher signal than with the probe touching the cuvette. Though the absolute amount of signal collected is lower than with the usual setup, a collection efficiency in the order of 60% still allows for reliable measurement results at only a slightly prolonged measurement time. Of course the probe can not only be used to investigate liquid samples in a cuvette, but also other type of samples. If you are interested in further details, please request our Tech Note about the FluoTime 100 equipped with a fibre probe. All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice. |
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