**3. Conclusions**

*2.4. Total Internal Reflection Ellipsometry* 

**Figure 5.** A competitive immunoassay for zearalenone (ZON) carried out by detection via total Within project Aquafluosense, successful development resulted in a modular instrumentation setup for fluorescence-based determination of several characteristic parameters of water quality. The application of fluorescence, as an analytical signal in an enzymelinked immunoassay format, results in a method of improved sensitivity with a lower LOD value than in the colorimetric ELISA (0.09 and 0.25 ng/mL, respectively). Moreover, resorufin-based determination proved lower LOD than application of OPD in colorimetric assay (LODOPD = 0.85 ng/mL). This benefit of this is that it allows determination of lower

internal reflection ellipsometry (TIRE). (**a**) A typical set of Δ(λ) spectra measured on bare Au sur-

and 0.1 ng/mL (8). (**b**) Changes in the adsorbed layer thickness versus the concentration of ZON

(in the mixture with Ab-ZON) obtained by fitting the TIRE data.

pollutant concentrations in surface water, which contributes to more effective monitoring. The detection results were validated by HPLC instrumental analysis and by a TIRE immunosensor method. Although the sensor technology provided orders of magnitude lower LOD than the immunofluorescence method developed, the great advantage of the latter is that it makes in situ determination possible, and the 96-well microplate format used in the immunofluorescence determination prototype allows an assay capacity of 25 samples in parallel in triplicates (with standard curves of seven calibration points). An in situ detection module with a dynamic detection range between 0.4 and 400 ng/mL was developed for ZON. The immunofluorescence method and the instrument prototype constitute a part of the Aquafluosense modular instrument family for determination of characteristic water parameters and contaminants.
