Page 258 - Tandem Techniques
P. 258
Page 240
The trap comprised a quartz tube, 23 cm long, 3.7 mm O.D., 1.9 mm I.D. which was fitted with two
heaters. The first heater maintained the temperature at 850-900°C Mercury free oxygen was fed into
the gas stream from the capillary column of the gas chromatograph, and the solutes were burnt in this
first heated section. A valving system between the capillary column and the interface permitted selected
peaks to be diverted to the trap as required. Subsequent to the combustion furnace was a section of tube
containing gold-platinum wire (85% gold-15% platinum) that trapped all the mercury compounds by
amalgamation. The section of the tube was also surrounded by a heater. When trapping was complete
the mercury was desorbed from the gold-platinum wire by heating, and the mercury vapor was swept
into the MIP atomic emission spectrometer. The results from this interface together with those obtained
by the solid phase extraction procedure previously described are shown in Figure 6.11.
Figure 6.11
Measurement of Traces of Mercury in Natural Gas Condensate by Super
Critical Fluid Extraction and by Selective Amalgamation (ref. 10)
It is clear that the amalgam interface produces the highest sensitivity and it is seen that he back ground
noise is extremely low. The trace from the
