Tuning the performance of room temperature phosphorescence sensing materials for oxygen using factorial designs

The effects of three experimental factors (pH, precursors, alcohol) on the sensing characteristics of these materials were screened by means of two-le vel factorial designs. The resulting materials turned out to be useful as l uminescent probes for the measurement of dissolved and gaseous oxygen. The photochemical properties and the analytical performance of the RTP sensing phases have been studied by using both gas now-injection analysis and conti nuous liquid now-through systems. The proposed sensing materials were parti cularly suitable for measuring dissolved oxygen in natural waters. The dete ction limit attained was 0.004 mg.ml(-1) and a typical precision of +/- 1.0 % at a 0.6 mg.ml(-1) oxygen level was achieved. Response time for 90 % of the final RTP value was less than 90s in a continuous flow mode. No hystere sis effects were noticed.