Purge off time

Overview of the Instrumentation Band-Broadening and Band-Focusing Mechanisms Setting the Temperatures Setting the Flows and Purge off Time Optimization Recommendations... 

A3.9.2 Position a slop can under the needle valves. Open the shut-off and needle valves and purge the probes for one minute (or sufficient time to purge 10 times the volume in the probe line). 

Desorption of the analytes takes place in the first minute. The second minute is for cleaning or baking-off purposes. This time of exposure does not need to be carefully monitored and may vary widely, provided that the fiber is exposed in the injection port for at least the length of time that the purge is off. 

The tips of the test swabs were cut off and placed in labeled plastic vials. One ml of 1M HNO was added, the samples were agitated and allowed to leach for 15 min. A 10 yul aliquot was placed on the tantalum strip and the purge gas flow was started (At alone for Sb and Ar H2 for barium). The atomizer unit was automatically cycled through preset time for drying, ashing and atomization (at 2500°C). Absorbance values were recorded on the chart recorder and results were obtained by comparison with a standard curve prepared for each tantalum strip. 

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