Optional Equipment
Internal Permeation Span Source
9-8
Model 43i Trace Level-Enhanced Instruction Manual
Thermo Fisher Scientific
2.
Insert the permeation tube carefully. Do not touch with fingers.
3.
Turn on the instrument.
4.
Wait 48-72 hours for the permeation tube to stabilize.
5.
Carefully remove the permeation tube from the oven and weigh to an
accuracy of 0.1mg. Perform this measurement as quickly as possible.
6.
Replace the permeation tube into the oven of the instrument.
7.
Repeat Steps 5 and 6 after two weeks.
8.
Compute the weight loss of the permeation tube from the values
determined in Steps 5 through 7.
9.
Repeat Steps 5 through 8 until the weight loss has been determined to a
precision of 1-2%.
10.
For the most accurate work, use the permeation tube in the same oven
that was used to determine the weight loss of permeation tube.
Use the following procedure to determine the release rate by transfer
standard.
1.
Make sure the oven has been calibrated as described in the “Permeation
Tube Oven Calibration” procedure described previously. Also make
sure that the Transfer Standard has been properly calibrated.
2.
Determine the permeation rate for the permeation tube in the Transfer
Standard, or install a certified permeation tube.
3.
Allow the permeation tubes in both the 43
i
and the Transfer Standard
to stabilize for at least 48 hours.
4.
Carefully calibrate the 43
i
using the Transfer Standard. The output of
the Transfer Standard should be connected to the SAMPLE bulkhead
on the rear panel of the 43
i
.
Determining
Release Rate by
Transfer Standard
