Measurements by fluorescence spectroscopy are subject to many more instrumental and physical variables than absorption measurements. Due to these effects, the same sample may not give identical results with different instruments even if they are of similar design. Physical effects such as quenching or self-absorption may lead to departures from expected concentration/emission relationships over quite narrow concentration ranges. For these reasons it may be impossible to produce universal “absolute” reference materials, as certified values may be instrument dependent. Provided homogeneity and stability can be established, however, reference materials can be produced that allow users to monitor the performance of a spectrofluorometer over time and can also indicate the relative performance of different instruments. Starna fluorescence references are produced in an ISO17034 accredited production facility and calibrated in an ISO/IEC 17025 accredited calibration laboratory. Several of these references are cited in USP Chapter <853> for spectrofluorometer qualification. 

Spectral Response & Linearity - Starna Quinine Sulfate References 

Used to qualify the spectral response of a spectrofluorometer and can also, over a limited concentration range (up to 1 mg/l), be used as a linearity check. USP cited reference.   

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Sensitivity & Signal to Noise Ratio - Starna High Purity Water Reference  

 
This Reference Material uses Raman scattering to simulate the behaviour of fluorescent materials at very low concentrations and can be used to determine the Signal to Noise Ratio of a spectrofluorometer near its limit of detection and hence indicate its ultimate sensitivity. USP <853 > cited reference.

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Spectrofluorometer Performance and Wavelength Validation - Starna 6BF Series 

 

Used for spectrofluorometer wavelength qualification,  as a routine check of spectrofluorometer  performance and for inter-instrument and inter-laboratory comparisons. Six polymer blocks  containing seven organic fluorophores. Excitation range from 260 to 600 nm and emission range from 370 to 670 nm

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Phosphorescence Decay Rate and Fluorescence Lifetime -  Starna Europium III Phosphorescence Reference

 
Used to confirm measurement of transient fluorescentsignals. Polymer block doped with Europium III. Decay rate and phosphorescence lifetime certified for gate times of  50 μS and 2 μS and a measurement delay time of 0.1 mS using excitation and emission wavelengths of 340 nm and615 nm respectively.

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Starna  Quantum Counter - Rhodamine  Solution Cell

 

Used by instrument manufacturers as a quantum counter  to determine spectral response factors to calculate ‘corrected’ fluorescence spectra. Designed to provide unity quantum conversion, so that the emitted fluorescence is directly proportional to the intensityof the exciting radiation. Usable range 220 nm – 580 nm. 

 

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Starna Quantum Yield Reference – Dilute Rhodamine in Ethanol Cell 

 

 

Quantum yield of this solution is 1.0 at 25°C. Working excitation range 450 to 465 nm and emission range 550 to 650 nm. Blank-corrected absorbance of this solution is below thelevel recommended in the literature to avoid internal filter effects. Dilute Rhodamine 101 in ethanol in a sealed quartz cuvette with ethanol blank.  

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Microplate Fluorometer Qualification - Starna Doped Glass Microplate References

 

For routine qualification of fluorescence-based plate readers for fluorescence intensity and well-to-well reproducibility.  96-well microplates containing inorganic fluorescent reference materials in glass matrix. The inorganic fluorophores are inherently stable, and do not suffer from photodegradation or bleaching.Formerly manufactured and supplied by Matech, USA. Available in top- and bottom-reading configurations. Range of excitation and emission wavelengths to match the user’s application. 

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