Thermo Scientific Orion 310, Instruction Manual

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PerpHecT ® Orion 310, 320, 330 Instruction Manual
Chapter V
General Information on
pH Calibration for Orion 310
A one or two-point calibration should be performed using fresh buffers
before pH is measured. It is recommended that a two buffer calibration,
using buffers that bracket the expected sample range, be performed at the
beginning of each day to determine the slope of the electrode. This serves
the dual purpose of determining if the electrode is working properly, and
storing the slope value in memory. For maximum accuracy, perform a
one-buffer calibration every two hours to compensate for electrode drift,
using a fresh aliquot of pH 7 buffer.
When operating in the LogR mode, the meter does not require the use of a
separate ATC probe. The PerpHecT meters measure the resistance of the
pH sensing glass and converts the value to temperature-compensated pH
measurements. For optimum results, PerpHecT electrodes or PerpHecT
ROSS electrodes should be used.
For best results, it is recommended that the unit be calibrated for
temperature in the LogR mode. Alternately, an ATC probe may be used.
If LogR or an ATC probe is not used, all samples and standards should
be at the same temperature or manual temperature compensation should
be used.
Stir all buffers and samples with a magnetic stirrer while a measurement is
being made.
NOTE:
Some magnetic stirrers generate enough
heat to change solution temperature. To avoid this,
place a piece of cardboard, foam rubber, or other
insulating material between the stir plate and
beaker.
Always use a fresh aliquot of buffer whenever calibrating.
General Information on pH Calibration for Orion 310