Question

FIA Multiple Choice Question

Q1. Answer the following multiple choice question

A) Which of these traces shows the effect of insufficient reagent in a single line normal FIA system?

1)

2)

3)

4)

B) Segmented flow is characterised by:

1) alternating sample and reagent sections

2) bubbles separating samples and wash solutions

3) laminar flow

4) dispersion

C) Axial dispersion occurs;

1) when bubbles are injected into the FIA system

2) when the pump rate is increased

3) along the length of the fia tubing

4) across the diameter of the tubing

D) Which of these traces shows the effect of insufficient reagent in a dual line normal FIA system in which the reagent is added to the sample online?

1)

2)

3)

4)

Answer 1

"Segmented flow is characterized by the reaction stream is segmented with bubbles of air or nitrogen to reduce inter sample dispersion. these are no air bubbles in the reaction stream the ""dispersion"" in the system is used to mix the samples and reagents axial dispersion occurs * axial dispersion is investigated in coiled flow inverters and helically coiled tubes. * coil to tube diameter ratio influences the intensity of axial dispersion * dispersion number correlates with the Reynolds number according to a power law single line normal system: - schematic diagram of single line system: - dual liner normal system: - ""if we inject a 2nd sample at a time ""t"" injecting the 1st sample there is little overlap of the two cloves we obtain max possible sampling rate. heights and return time are by the dispersion of samples flow effect of return time T: on sampling frequency "