Fluorimetric flow through sensors for pesticides based on a "host guest" recognition mechanism

Flow-through optosensors for warfarin and carbaryl are described in this pa per. The sensors are developed in conjunction with flow injection analysis systems and make use of a bound b-cyclodextrin material and a synthetic pol ymer, respectively, as sensing phases. The proposed sensor for warfarin exh ibited a detection limit of 6.3 10(-8) M warfarin. Precision, evaluated as the relative standard deviation of five measurements at a 1.0 10(-6) M warf arin level, turned out to be around 0.58. The analytical performance charac teristics of the proposed carbaryl sensor were as follows: defection limit were 6.5 10(-8) M and 2.5 10(-8) M for aqueous and organic medium, respecti vely, with a relative standard deviation lesser than 5% for 9.45 10(-7) M o f carbaryl. Possible recognition mechanisms are proposed.