Page 427 - Tandem Techniques

Page 410

It is seen that excellent selectivity can be obtained, eliminating the need for high resolving power
columns, as the multitude of interfering hydrocarbons present in gasoline are not detected.

Ajilec and Stupar [9] developed a very similar LC/FAA system for monitoring Fe ++ and Fe+++ in
wines. The apparatus they used is shown in Figure 10.4.

Figure 10.4
An In Exchange LC Coupled to a Babington
Nebulizer for the Determination of Iron in Wine (ref. 9)
The simplicity of the tandem system is quite remarkable. The separation of the ion species was achieved
with a Dowex 50-X8 (50-100 mesh) column 7.5 cm long and 10 mm I.D. The peristaltic pump provided
flow rates between 1 and 4 ml/min. The outlet from the column was fed directly to a Babington
nebulizer and the resulting spray passed directly to a flame AA spectrometer. The curves monitored by
the flame AA were somewhat asymmetrical but the two iron species were well separated. The limit of
detection for iron in wine was found to be about 15 µg/ml with a relative standard deviation of 3%.
These limits of detection are not as low as that produced by direct sampling but the LC/MS provides
information on speciation as well as the total iron content of the wine