Hitachi ZA3000 Series, Инструкция по эксплуатации

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4.3 Working Curve Graph
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(2) Changing the STD Unit
To change, input a desired unit in the [STD Unit] input
column and click the [Recalculate] button.
(3) Changing the Number of STD Digits below Decimal Point
To change, directly input a value in the [STD Decimal
Place] input column or set the desired value by clicking the
button (up/down) at the right of this column.
(4) Shifting the Zero Point of Working Curve (0-Point Shift)
If the created working curve does not pass through the zero
point (concentration 0, absorbance 0), the curve can be
moved in parallel with the ordinate so that it passes through
the zero point. The concentration value of an unknown
sample remains unaffected.
For zero point shift, set the ON status and click the
[Recalculate] button.
The data subjected to zero shift can be reset to the original
status by setting the OFF status and clicking the
[Recalculate] button.
(5) Weighting
Depending on the range of the working curve, the results of
measuring low concentration may be affected by the
absorption level of the highly-concentrated standard
solution. To reduce such impact, you can use a working
curve calculation formula suitable for low concentration.
The general weighted working curve formula for “None” is
as follows:
 
 
2
2
,


 
n
l i
i i
y x a y x
y(a,x
i
) is the working curve formula and a y(a,x
i
) which
minimizes the sum of the square of the difference between
the calculated value and the measured value for each STD
is calculated.
The weighted working curve uses a calculation factor to
weigh low concentration by adding “W
i
”.