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. Such references are referred to as “Reference Materials” (RMs) or Quality Control Materials (QCMs). Starna produce a range of such materials under the same tight quality control procedures as are applied to their CRMs.

For the reasons outlined above, instrument  qualification may only be valid for  a particular instrument and within a relatively narrow range of operating parameters – indeed it can even be method specific. The references listed below will cater for many routine situations,  but Starna can also design and supply fluorescence Reference Materials tailored to individual needs. 

Spectral Response - Starna Quinine Sulfate References

Fluorescent Intensity Certified Reference - Quinine Sulphate 

This Reference Material can be used to calibrate the spectral response of a spectrofluorometer over the wavelength range 375 nm to 675 nm. It can also, over a limited  concentration range (0 – 1 mg/l) be used as a linearity check.

 

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Performance Validation - Starna Polymer Block References

 Broadband Fluorescent Wavelength Reference - 6BF Set

These convenient solid materials may be used on a routine basis to calibrate and monitor the performance of Fluorescence Spectrophotometers. They contain seven fluorescent compounds whose spectra cover a wide wavelength range, enabling users to select a  reference material with broadly similar spectral properties to those of their analyte. A similar material containing Europium (III) is available for  evaluating phosphorescence measurements.

 

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

 Fluorescence Intensity Correction Reference - Ultra-pure Water

This Reference Material simulates the behaviour  of fluorescent  materials at very low  concentrations and so can be used as a Quality Control Material (QCM) to determine the Signal to Noise Ratio of a spectrofluorometer near its limit of detection and hence indicate  its ultimate  sensitivity.

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Quantum Counter - Starna Rhodamine 101 Solution Cell

 Front surface spectral correction Reference - Rhodamine B (Quantum Counter Method)

This design is used by several instrument manufacturers as a quantum counter  to determine spectral response factors.

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