Teledyne 5000B Operating Instructions Manual page 77

A zero may be established with a reproducible simulated (offset)
zero absorbance fluid in the sample cell of the analyzer. When
possible this fluid should be stable for H2O content and should
approximate the process being measured to minimize the offset
zeroing, otherwise, dry air or nitrogen can be used. The analyzer
must first be calibrated for sensitivity full scale by using known
certified/analyzed samples containing the component (analyte(s) to be
measured.
NOTES:
These samples (low/mid/high about 1 liter each) must be
prepared and provided for introduction into the zero and/or
span port of the sample system, with outlet collected from the
cal return port of the sample system. A 500 to l liter glass
syringe with Luor-loc to 1/4" tube connections should be used
for introducing the samples into the analyzer sample cell for
zero and span cal adjustments. These are introduced through
the calibration ports usually labelled zero or span fluid inlets.
The exiting samples when nontoxic are usually collected in
waste containers from the cal-return port of the instrument
cabinet. These cannot be used again as water vapor from
containers and atmosphere will contaminate them. They would
require analysis again before reintroducing for correlation
purposes. Also, its is a good practice to flush copiously the
sampling train with each calibration sample prior to accepting
any read value. Each sample should be allowed to stabilize
before reading. When a N2 flush is used to dry the sampling
train before each sample is read, the readings will come to
equilibrium faster since no water cross-contamination should
be evident or occur.
11 IF CALIBRATION PROCESS REPRESENTATIVE SAMPLES
CANNOT BE OBTAINED,
THEN A DIRECT ON-LINE TWO-POINT CALIBRATION APPROACH
CAN BE USED AS FOLLOWS:
Assuming customer has designed in a sampling valve (this
valve may contain a chromatographic septum port for a needle,
i.e., for toxic or flammable samples at low pressure), hookup
for a sampling bomb (high pressure), grab sample port, or
sealed container to draw off representative process grab
samples. Note: All samples are brought to the analytical lab
for speedy analyses (preferably analyzed within 15 minutes) to
correlate to process conditions. The sample analyzed should
be by an analytical method with an acceptable precision and
accuracy as used to normally monitor the process and confirm
the on-line analysis. The on-line analyzer is only as accurate
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
Operations/Analysis Unit 4
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