Could anyone tell me the "working"/practical absorbance range for a static UV detector. I have been analyzing standards at 0.02 to 0.2 abs and notice the blank reading can be 0.0001 to 0.01 abs. The variability in the blank can be significant, thus lead to high variability in the sample absorbances. The system has been check:
-diagnostic test passed (lamp intensity okay)
-samples degass
-similar results with two same manufacture instrument and different manufacture instrument
-very low variability in repeat reading of the same solution in the cuvette over time
-high variability in reading after changing the solution in the cuvette (solution mixed adequately prior to taking multiple aliquotes for UV analysis)
-noticed significant rise in the blank baseline even at 400nm for different manufacture intrument

Is it practical to analyze samples and stds <0.2Abs unit?