Abaxis VETSCAN VS2 Manual Del Usuario página 97

The equation for calculating absorbance is this:
where:
A = Absorbance at wavelength 1, referenced to wavelength 2
I = Intensity of light transmitted through the reaction cuvette at wavelength 1
1RC
I = Intensity of light transmitted through the reaction cuvette at wavelength 2
2RC
I = Intensity of light transmitted through the dark cuvette at wavelength 1
1
0
I = Intensity of light transmitted through the dark cuvette at wavelength 2
2
0
I = Intensity of light transmitted through the open cuvette at wavelength 1
1OC
I = Intensity of light transmitted through the open cuvette at wavelength 2
2OC
This is the basic equation for measuring analyte concentrations in the rate methods and endpoint reac-
tions used in chemistries.
9.2.1 Rate Methods
The rate of the reaction is calculated from the difference between absorbances measured at certain
defined intervals on the linear portion of the reaction curve. Absorbances are taken throughout the read
time to confirm the linearity of the reaction curve. The absorbance rates are converted to analyte con-
centrations using the rotor-specific calibration factors encoded on the bar code ring.
The equation for rate methods is:
{
-log
where:
A/ = Rate of change of absorbance
F = Measurements taken at time F on linear portion of reaction curve
B = Measurements taken at time B on linear portion of reaction curve
t = Time in minutes
I = Other intensities, same as described above
XX
(I λ1RC - I λ1
A = -log
(I λ1OC - I λ1
(I λ1RC - I λ1 ) / (I λ2RC - I λ2 )
0 0
(I λ1OC - I λ1 ) / (I λ2OC - I λ2 )
0 0
Principles of Procedure and Operation
) / (I λ2RC - I λ2
0
) / (I λ2OC - I λ2
0
} {
(I λ1RC - I λ1
-log
(I λ1OC - Iλ1
F
Time Period
)
0
)
0
}
) / (Iλ2RC - I λ2 )
0 0
) / ( I λ2OC - I λ2
)
B
0 0
9-3