The effects of flow rate-lamp intensity interdependence on dye-sensitized continuous photochemical analysis : applications to procaine

The applicability of dye-sensitized continuous photochemical analysis (hereafter DCPA) to a new substrate is demonstrated. Data are presented on the conditions for the measurement of procaine using Rose Bengal as the dye-sensitizer. DCPA apparatus has been modified so that the effects of the flow rate-lamp intensity interdependence on the detector response can be measured using an intensity selection method which does not vary the filament temperature of the photolysis lamp(s). Effects of dilution on the detector response as a function of flow rate are determined. Substrates in DCPA are classified into two groups: 1. a class including nicotine, having no back reaction and being photon limited at high flow rates; 2. a class including procaine, having an interferring back reaction. Calibration curve for procaine at 50 ml/min and 750 W is linear, having a slope of 276 mAbs/mM, while the calibration curve at 250 ml/min and 2250 W is nonlinear, yet having an approximate slope of 520 mAbs/mM. Determination can be done from 4 x 10[raised to -5] M to 1 x 10[raised to -3] M original procaine concentration.