Effect-directed Analysis (EDA)

A bioassay measures a particular effect of a substance, but does not identify the substance itself. In the case of an unexpected or increased bioassay response, the question remains: which substance is responsible for this? Effect Directed Analysis (EDA) is used to answer this. EDA is a combination of bioassays, liquid chromatography and screening. An (extract of) a water sample is separated via an LC column. The eluate is split in parts, and one part of it is sent to a mass spectrometer. The other part is collected in very small fractions and every fraction is then tested in a bioassay with a relevant effect as endpoint, such as genotoxicity or hormone disruption. The fractions which showed an effect contain a relevant chemical. The fractions correspond to a certain peak of the same chemical at the same retention time in the mass spectrometer. By using targeted or untargeted screening, the identity of the chemical is determined.

In collaboration with fellow researchers from the VU in Amsterdam, Het Waterlaboratorium has developed and implemented an EDA platform that performs fractionation at a very high resolution. A high correlation between bioassay activity and signal in the mass spectrometer can be achieved. As a result, the chance of successful identification of active substances is higher. The method is schematically depicted in the figure below.

Information and examples of applications of the EDA platform at HWL can be found here:

In the project “RoutinEDA”, continuous research is done to improve the EDA platform. You can find information about this here


More information about Effect-Directed Analysis in general can be found here: