UV-2000S Absorbance Sensitivity

Absorbance sensitivity of the UV-2000S vs. UV-1000S

Accurate SPF & UVA results even with highly absorbing formulations

The UV-2000S provides a minimum absorbance sensitivity of 2.7A at all wavelengths between 290 and 400nm. This exceeds the 2.2A requirement of the 2007 Colipa UVAPF method and helps to ensure that the UV-2000S can be relied upon to give accurate SPF, UVAPF and Star Rating results even with the highest factor sunscreens (SPF 50+).

The charts above compare the absorbance sensitivity of the original Labsphere UV-1000S (top) with that of the UV-2000S (bottom). We tested both instruments using the validation method described in the 2007 Colipa UVAPF method. We took two of the special Schöneberg PMMA plates that have been doped with UV absorbers and measured the spectral absorbance of each plate separately. We then placed both plates in the instrument and measured the combined absorbance.

For the UV-2000S, the absorbance of the two plates measured together exactly equalled that for the sum of the two individual plates at all wavelengths. This serves to confirm that the UV-2000S possesses an absorbance range that is linear to over 3A.

For the UV-1000S, the more limited dynamic range means that the measured sum of the two PMMA plates (blue line) did not match the theoretical summation of the absorbance of the two individual plates (purple dashed line).

There are several conclusions to be drawn from these tests.

Based on dynamic range, the UV-1000S does not comply with the requirements for absorption sensitivity stated in the 2007 Colipa UVAPF method.
The UV-2000S does comply with the 2.2A minimum absorbance sensitivity specified by Colipa.
The accuracy of SPF, UVA ratio and Star Rating values provided by the UV-1000S will start to decrease for sunscreen formulations possessing high protection factors.