Abstract
The room-temperature phosphorescence (RTP) of six phenothiazine derivatives was investigated using a solid substrate (PVA-CLL) prepared from a mixture of poly(vinyl alcohol) (PVA) and a small amount of cellulose (CLL, 5 wt%). The sample solution spotted substrates were conveniently dried in a microwave oven. The RTP signals of these phenothiazine derivatives could be measured sufficiently, even without any dry gas flush to the sample compartment, since the signals were very stable in the atmosphere. The limits of detection for the phenothiazine derivatives were in the 0.16-2.53ng/spot range; these values proved a higher sensitivity of the PVA-CLL substrate compared with those of filter paper. The calibration curve of promethazine was examined as an instance of these phenothiazine derivatives, and the linearity was confirmed with a correlation coefficient of 0.997 (n=24) in the range from 2pmol/spot to 1nmol/spot. The relative standard deviation was 10.6% (n=5) at a level of 40pmol/spot. These results suggest that the PVA-CLL substrate has superior advantages for determining phenothiazine derivatives by the RTP method.
