Flow rate is an important instrumental factor which can affect
the DI of the CL system. So, the effect of the flow rate of peristaltic
pump was studied over the range of 1.0–4.0 mL min1. The DI signals
increased with the increase of the flow rate up to
2.8 mL min1 and then remained constant. Also, the highest DI signal
was obtained when the flow rate of the pump was
2.8 mL min1. Hence, flow rate of 2.8 mL min1 was selected for
the following experiment. The length of the mixing tube on the
DI signals was investigated between 5 and 20 cm and for the purpose
of obtaining the maximum CL signal in the flow cell the optimal
length of the mixing tube selected for further experimentation
was 10.0 cm.