Implementation of multicommutation principle with flow-through multioptosensors

For the first time, the combination of multicommutation concept with flow-through multioptosensors is exploited and a biparameter multicommutated UV sensor is developed. A very easy-operated and automated sensing device is proposed here and demonstrated to be useful in the routine analysis by applying it to the determination of two widely used pharmaceuticals chosen as model analytes: salicylamide and caffeine. The particulated solid phase used performs two functions: (a) states selectivity conditions by itself in the flow cell and (b) provides appropriate separation of the analytes in the on-line precolumn, thus making possible the sequential arrival of the analytes to the detection zone. Both carrier and eluting solutions chosen allow (with a very simple solenoid valve configuration and operation) the transitory signals to be developed in a completely automated device. Drastic reduction of carrier and eluting solutions used are achieved as compared to typically FIA optosensor configuration. The sensor responds linearly in the range 2-30 and 1-14 μg ml−1 for SLC and CF, with detection limits of 0.33 and 0.15 μg ml−1, respectively. Solution savings between 50 and 85% were obtained when comparing to typical flow injection analysis (FIA).