Reaction Linearity Check - Hitachi 902 Service Manual

3) Reaction Linearity Check

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In a rate assay test, the linearity in absorbance change is checked.
Check value varies with the number of points (N) in photometric range.
< When N ≥ 9 >
The difference in absorbance change quantity between the first-half 6 points (5 sections)
and the latter-half 6 points is obtained and then divided with the overall absorbance
change quantity. When the result of this calculation exceeds the limit in linearity check,
comment LIN. is printed together with the result of measurement.
∆Af − ∆Ab
× 100 > Linearity limit value.....LIN.
∆A
< When 4 ≤ N ≤ 8 >
The difference in absorbance change quantity between the first-half 3 points (2 sections)
and the latter-half 3 points is obtained and then divided with the overall absorbance
change quantity. When the result of this calculation exceeds the limit in linearity check,
comment LIN.8 is printed together with the result of measurement.
∆Af − ∆Ab
9 9
∆A
9
• ∆Af, ∆Ab and ∆A in the above formula are all converted into absorbance change in a minute
by the least squares method.
• In the following cases, reaction linearity is not checked.
a) The number of photometric points (N) within the reaction limit is 3 or less ("reaction limit
over" will occur).
Absorbance change in a minute is 60 × 10
b)
smaller than 60 × 10
Fig. 2-2 Reaction Linearity Check
× 100 > Linearity limit value.....LIN.8
-4
.
-4
Abs or less, or |∆Af - ∆Ab| is equal to or
2 - 55