Kinetic fluorometric FIA determination of total ascorbic acid, based on use of two serial injection valves

The kinetic determination of total ascorbic acid with a flow-injection analysis system is described. The sample is loaded into two serial sample injection valves and injected into a carrier system containing mercuric chloride and o-phenylenediamine. The formation of a fluorescent product is monitored. The single-point and double-point kinetic methods are compared by using both peak height and peak area as the analytical signal. A detection limit of 0.1 mu/ml for vitamin C was achieved with a sample throughput rate of 30 per hour.