Phosphorescence properties of p-aminobenzoic acid immobilized on a nylon membrane.
The properties of nylon as a new material for obtaining room-temperature phosphorescence from p-aminobenzoic acid (PABA) have been investigated. Although PABA shows native phosphorescence when adsorbed on a nylon membrane, a significant improvement in both sensitivity and limit of detection is achieved in the presence of alpha-cyclodextrin and heavy atoms. An additional enhancement of the phosphorescence signal is attained when the measurements are carried out under a nitrogen atmosphere. The analytical figures of merit obtained under the best experimental conditions are: linear calibration range from 0.6 to 6 ng/spot (the lowest value corresponds to the quantitation limit); correlation coefficient, 0.998 for 18 data points; relative standard deviation, 2.2% (n = 5) at a level of 2.4 ng/spot; and limit of detection, 0.2 ng/spot (calculated according to Clayton's definition).
Escandar
Graciela M
GM
Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531 (2000) Rosario, Argentina. gescanda@fbioyf.unr.edu.ar