Discovery Tools

10 years of supplying fluorescence lifetime tools since 2000 


Fluospec FL Plate Readers
Fluorescent dyes
Kinase assays
Aminopeptidase assays
Caspase assays
Careers at AssayMetrics
Assaymetrics People
Contact us

PURETIME fluorescence polarization

PURETIME dyes have characteristically long fluorescence lifetimes. This makes them interesting as fluorescence polarization probes. Short lifetime fluors such as fluorescein, Rhodamine, Alexa, BODIPY or cyanine dyes produce highly polarised emission when attached to even modest sized biomolecules. PURETIME dyes do not emit highly polarised fluorescence until they are either in highly viscose environments or attached to proteins that rotate slowly in solution.



bulletMeasure changes in molecular weight at more than 40,000 Da
bulletMeasure changes in viscosity at more than 400 mPa.s
bulletDiscriminate against elastic scatter and reflection in challenging assay situations


Polarization characteristics

As an example, the figures below compare the fluorescence polarization of PURETIME 22 with fluorescein under similar conditions. All polarization measurements were performed with a BMG Fluostar platereader equipped with a polarising optical fibre head.


Perrin equation plot showing intercept at Pzero=400mP


Perrin equation plot showing intercept at Pzero=450mP


Although the two dyes have similar Pzero values,  PURETIME 22 doesn't plateau until attached to much higher molecular weight molecules as the Perrin equation plot shows below:



Perrin equation plot showing increased measurement window for PURETIME22




Information Request Form

Select the items that apply, and then let us know how to contact you.

Send information on PURETIME fluorescence polarization 
Send company literature
Have a salesperson contact me


Home ] Fluorescent dyes ] Kinase assays ] Aminopeptidase assays ] Caspase assays ] FLIM ] Polarization ] Documents ] Careers ] People ] News ] Contact us ]

Copyright 2008 AssayMetrics Limited
Last modified: May 25, 2011