Sensors based on integrated retention and luminescence detection

1 Sensors based on integrated retention and luminescence detection 

Fluorimetry excels photometry for detecting analytes and products by means of sensors on accoimt of its higher sensitivity and the also higher selectivity arising from the small number of species that can emit previously absorbed energy in a radiant form. As a rule, the fluorescence of an analyte or reaction product increases on retention on a solid support as a result of losses 

The first such sensor, developed for the determination of fluoride ion, relies on the formation of the zirconium(IV)-Calcein Blue-fluoride complex 

The cyanide sensor developed by the authors group is based on the formation of an addition product between cyanide ion and pyridoxal-5-phosphate, and its subsequent retention in the sensor (a fluorimetric flow-cell packed with QAE-Sephadex resin). The eluent is not injected, but merged with a stream of 0.05 M HCl after the reactor that is used both to acidify the complex and elute it after measurement. The calibration graph for the target analyte was linear from 50 ng/mL to 3.0 pg/mL, and the relative standard deviation and sample throughput were 1.4% (for 2 pg CN7mL) and 

10 samples/h, respectively. The selectivity of this sensor is clearly higher than that of conventional continuous methods, both fluorimetric and photometric [67]. 

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