POLY(VINYL ALCOHOL) AS SOLID SUBSTRATE MATERIAL FOR ROOM-TEMPERATURE PHOSPHORIMETRY

A mixture of poly(vinyl alcohol) (PVA) and a small amount (5%) of cellulose (CLL) was pressed under similar to 280 kg/cm(2) to form a disk of 1 mm thickness, and the prepared disk was used as a solid substrate for room-temperature phosphorescence (RTP). The addition of CLL was to reduce the fragility of the disk and enhance the permeability of sample solutions into the disk surface. The sample solution spotted PVA-CLL solid substrates were dried in a microwave oven conveniently. The efficiency of PVA-CLL solid substrates was monitored by RTP intensity of p-aminobenzoic acid (PABA) spotted on them, and the results showed that the RTP signal of PABA was largely enhanced as compared to that on the conventional paper solid substrates. Another prominent feature of the PVA-CLL solid substrate is that the RTP signal can be observed sufficiently even without a dry gas flush during the RTP measurement, while a dry gas hush is essential for the conventional substrates. A calibration curve for PABA was linear from 7.3 to 1200 pmol/spot. The results for the RTP measurements of chlorpromazine hydrochloride and tetracaine hydrochloride were also reported. The limits of detection of PABA and the other two drugs were 0.03, 0.16 and 1.26 ng, respectively.