Chapter 4
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Water Analysis Test Menu
44
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Orion AquaMate Spectrophotometer User Manual
Thermo Scientific
Creating or Modifying a Test Method
How to Define the Test Method Parameters
The Water Analysis test technique can be used with colorimetric reagents in addition to those
included on the AquaMate USB memory stick when the test kit manufacturer specifies the
wavelength and factor or equation (up to third order polynomials) required for obtaining the
concentration of the test kit.
When creating a new test method, the format for entering the factor or equation is:
Result = A + Bx + Cx
2
+ Dx
3
where x is absorbance at the set wavelength
When x is substituted with Abs, the following equation can be used:
Result = A + B*Abs + C*Abs
2
+ D*Abs
3
where A is a numeric value
B is a numeric value multiplied by absorbance
C is a numeric value multiplied by absorbance squared
D is a numeric value multiplied by absorbance cubed
For test kits that specify a simple
multiplicative factor, enter the factor as the
B value.
For example, a colorimetric test kit provides
a factor of 12.68.
The equation is: Result = 12.68*(Abs)
Where Abs is the measured absorbance at
the specified wavelength.
Set the factor as: B = 12.68
For test kits that specify an equation, decipher the A, B, C and D factors for the equation.
For example, if the equation given with a
test kit is: ppm (mg/L) = 2301 (abs) - 3
The equation is: Result = -3 + 2301*(Abs)
Set the factors as: A = -3
B = 2301
C = 0
D = 0