A fluorescent FIA sensor for flavonol

The ratio of EDMA cross-linker to MAA functional monomer was also examined. CHCI3 was again used as the porogen and 150 aliquots of 5.0 pM flavonol in a 70/ 30 (v/v) mixture of hexane/CHCl3 were injected into the system. Both the relative fluorescence intensity as well as the response time of the system generally decreased as the EDMA/MAA ratio was increased and, in particular, fluorescence intensities and response times for MIPs with EDMA/MAA ratios 0.4 were significantly reduced. Thus, the optimal polymer was deemed to be that with an EDMA/MAA ratio of approximately 0.25. This is unusual, as most MIPs, as well as the mixture indicated above, have an EDMA/MAA ratio of ca. 4/1. 

Using the optimal conditions determined above, the effect of the volume of porogen used in the polymerisation was examined. Volumes of CHCI3 from 0.6 to 1.5 mL had little effect on the response times, while volumes of less than 0.8 mL 

Toward optical sensors for biologically active molecules 

CHCI3 decreased the fluorescence intensity dramatically. Thus, further MIPs were prepared using 1 mL of porogen. The template/functional monomer ratio was also examined and it was found that a maximum fluorescence intensity was observed for flavonol/MAA ratios of ca. 0.1, while ratios from 0.01 to 0.5 exhibited significantly decreased fluorescence intensities but similar or slightly higher response times. Thus, this ratio was employed in the preparation of subsequent MIPs. 

The reproducibility of the sensor was also investigated by removing the template from the polymer and reloading it into the system. After three cycles, the signals from a single batch of polymer had values 80-97% that of the initial response. Between different batches of the MIP, this figure was found to be 93%. Moreover, the polymers were found to be mechanically stable after more than 2 months of continuous use. 

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Toward optical sensors for biologically active molecules 20.3.7 A fluorescent FIA sensor for flavonol... 

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