Abstract: The application of surface-enhanced Raman scattering (SERS) in quantitative analysis is demonstrated by the determination of 4-aminobenzoic acid(I) and acridin-9-amine(II) on silver suspensions by SERS in a flow injection system. Two peristaltic pumps were used to mix 2 mM NaBH4 and 1 mM AgNO3 and pump the resulting silver suspension through the flow injection analysis system. The flow injection analysis system is described (with diagram). The sample solution contained I in aqueous 40% ethanol or II in ethanol. The calibration graph was rectilinear for 4 to 100 µg mL-1 of I, and the coefficient of variation (n = 6) was 3.2%. The system required cleaning with 40% HNO3 after 10 to 15 injections.

Abstract: Decomposition of phenyl acridinium-9-carboxylate is monitored using electrogenerated chemiluminescence in a flow system. The formation of the pseudobase from the acridinium ester [AE] is described by rate = k'1[AE] + k''1[AE][OH-]0.5, where k'1 = 0.020±0.006 s-1 and k''1 = 2.1±0.8 (L/mol)-0.5 s-1. Irreversible decomposition of the pseudobase is described by rate = k'2[AE][OH-], where k'2 = 20.1±3.8 (L/mol s). These kinetic equations, plus measurement of variation in emission intensity for constant acridinium ester concentration, are used to predict the resulting emission intensity v. pH behavior given various contact times (in the 0.25 to 25 s range) for the acridinium ester to be in an alkaline solution prior to initiation of the chemiluminescence reaction.