Quantification of Unimolecular Photoreaction Kinetics: Determination of Quantum Yields and Development of Actinometers—The Photodegradation Case of Cardiovascular Drug Nisoldipine

Table 3

Dyes absorbance, overall reaction rate-constants, photokinetic factors, and percentage reduction in reaction rates of NIS photodegradation in the presence of various concentrations of TRZ and QY when irradiated and observed at 390 nm.

			/s^−1		% reduction^b
NIS^c	0	2.30	0.0080	1	0
Tartrazine (TRZ)	0.379	1.54	0.0052	1.54	35
	0.762	1.08	0.0039	2.05	51.25
	1.147	0.81	0.0032	2.50	60.00
	1.415	0.68	0.0022	3.64	72.5
Quinoline Yellow (QY)	0.261	1.73	0.0067	1.19	16.25
	0.472	1.40	0.0055	1.45	31.25
	0.792	1.06	0.0040	2.00	50
	1.137	0.82	0.0032	2.50	60

Absorbance of the dye measured at the irradiation wavelength of 390 nm for concentrations given in Figure 7.
^bThe constant concentration of NIS was 1.56 × 10⁻⁵ M.
^cThe radiant power value for the experiments was = 1.74 × 10⁻⁶  −  1.78 × 10⁻⁶ einstein·dm⁻³·s⁻¹.