[scienceaddiction1]

I am trying to measure the absorbance of samples which have varying levels of emulsified bisphenol-a in them with a spectrophotometer. I'm using the absorbance vs concentration setting and am also using a sample that does not have bisphenol-a as a calibrant.

However, when I go to measure the samples (same quantity and procedure) I get extremely small absorbance level differences (.001-.003) which are within the margin of error. I've tried this at 230 and 270nm wavelengths, which are said to be optimal for bisphenol-a detection.

The amount of BPA that should be in these samples is non-negligible and is high compared to real world scenarios.

What could I be doing wrong?

Thank you for any that can be offered!

[Orcio_87]

Does the small absorbance relates only to samples of smallest concentration or also every other sample ?

The amount of BPA that should be in these samples is non-negligible and is high compared to real world scenarios

Are these samples a field samples (taken to measure concentration of bis-phenol) or are they calibration samples ?