YOKOGAWA UV700G, User Manual

Page: 27 / 131

<2.Specification>
2-12
IM 12K01B02-01E
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TURB (turbidity) Measurement
TURB measurement is performed by using the visible light (VIS) absorbance.
The measurement method is the transmitting absorption method.
Calibration with the standard solution enables a simple measurement of TURB.
Measure in the measurement range of 200 deg. or below. If measuring in a measurement range
that exceeds the specified value, the linearity deteriorates due to the scattering light influence.
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How to Calculate the COD Conversion Factor
If it is judged that there is obviously a linear function between the measurement concentration
Xi (i = 1, 2, ...n) and corresponding manual analysis value Yi (i = 1, 2, ...n), the calibration curve
formula (regression formula) is expressed as follows:
Y = a
+
bX
The gradient of this regression line X-axis (b) and the Y-axis segment (b) can be calculated by
using the measurement value and the least-square method as in the following formula.
a=Y - bX
b= =
S
( X
i
- X ) 2
n
S
X
i
Y
i
- (
S
X
i
)(
S
Y
i
)
( X
i
- X )( Y
i
- Y )
n
S
X
i
2 - (
S
X
i
) 2
“a” and “b” are rounded to a value which is larger by 1 digit according to the number of significant
figures of the measurement value.