Principles Of Calibration - Thermo Scientific Orion 2111LL User Manual

Principles of
Calibration
Flow Cell Volume for DKA
Double-Known
Addition (DKA)
Thermo Scientific Orion 2111LL Sodium Monitor User Guide
ROSS and the COIL tradedress are trademarks of Thermo Fisher Scientific Inc. US Patent 6,793,787
Siphon Tube
Figure I-
Calibration .procedures .for .an .analytical .instrument .are .important .and .must .
be .performed .carefully . . . T he .calibration .procedure .used .in .the . T hermo .
Scientific .Orion .2111LL .is .a .variation .of .Double .Known .Addition .(DKA) .
using .ROSS .Ultra® .electrode .technology .and .patent-pending .flow .cell .
technology .in .combination .with .the .passive .diffusion .system . . . T his .method .
has .the .distinct .advantages .of .being .fast, .easy, .and .accurate .
Before .calibration .begins, .the .diverter .valve .is .turned .to .divert .flow .from .
the .measure .drain .to .the .re-circ .tube, .allowing .the .flow .cell .to .fill . .
The .two .air .valves .serve .dual .purposes .during .the .calibration .sequence .
The .first .function .is .to .stop .the .airflow .through .the .sample, .and .redirect .
the .airflow .to .the .headspace .of .the .flow .cell . . . T hus, .the .flow .cell .is .filled .
without .causing .air .bubble .disturbance .in .the .sensing .tube . . . T he .second .
function .ensures .proper .siphoning .operation . . . T he .combination .of .these .
functions .provides .an .accurate .volume .for .calibration .
At .the .first .step .of .the .DKA .calibration .the .actual .concentration .in .the .
sample .is .unknown . . . T he .instrument .measures .the .potential .(E
this .value .in .the .microprocessor . . .A .known .amount .of .standard .1 .solution .
is .added .to .the .flow .cell, .which .increases .the .concentration .(C
corresponding .known .amount .(dC
into .the .re-circ .tube, .thoroughly .mixing .sample .and .standard .in .a .closed-
loop .system . . . T he .new .potential .(E
when .stability .is .reached . . .Adding .standard .2, .preferably .10 .times .more .
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Sensing Tube
Siphon Drain
) . . .During .this .process, .air .is .pumped .
1
) .is .measured .and .stored .automatically .
1
General Information
) .and .stores .
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) .with .a .
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