A single line FIA configuration was used. A multichannel
peristaltic pump (ISMATEC, Switzerland) propelled the carrier
stream with a flow rate Q of 1.75mLmin−1. A 6-port-valve
(VICI, USA) was used to inject a sample volume Sv of 150L.
The sample loop was filled with a syringe. The construction
of the indicator electrode was described earlier [27].
The pH-sensitive electrode was connected with the injection
valve via a 10 cm long Teflon tube (inner diameter 0.5 mm).
As stated in,with this configuration optimal dispersion
coefficients for FIA titrations can be obtained. A KE
10 saturated calomel electrode with an electrode potential
of E = 244.4mV at 25 ◦C (Sensortechnik Meinsberg, Germany)
was used as reference electrode and was placed 2.5cm
downstream the detector cell. Chronopotentiometric measurements
were recorded using an AUTOLAB with a PSTAT 10
(Eco-Chemie, The Netherlands) in conjunction with a personal
computer (IBM compatible). All reactions were performed
at room temperature (23 ◦C). Sample time was chosen as
0.2 s.