Thermo Orion Star, Руководство пользователя

Страница: 68 / 111

Thermo Electron Corporation X-4 Orion Star Series Meter
ISE Technique
Preparation of Standards
The standards should be prepared in the same ISE units as required by the sample
results . It is preferable to use serial dilutions with volumetric glassware to obtain
the different concentration levels .
Note: Any reagents such as ionic strength adjustors, should be added to
samples and standards as specified in the electrode User Guide or Instruction
Manual.
s
The calibration points should bracket the expected concentration range of the
samples and there should be a tenfold change in concentration (i .e . 1 ppm and
10 ppm or 10 ppm and 100 ppm) .
Fresh aliquots of standard should be used at each calibration .
Prior to each day’s measurements, a two or more point calibration should be
performed . To verify the calibration the electrode should be placed in a fresh aliquot
of standard and if the value has changed the electrode should be recalibrated .
Recommended slopes are given with electrode instructions .
It is recommended that the calibration and sample measurements be taken at the
same temperature for greater accuracy and reproducibility .
Note:
For greater low-level measurement accuracy, a new low-level ISE
calibration option is available. An additional rinse of the electrode with the
next standard or sample solution is recommended for any low level
measurements.
s