Thermo Scientific MIRAN 205B Series, Instruction Manual, Page: 93 / 214

Chapter 7 Configuration and Setup
7-39
┌────────────────────────────────────────┐
│╒═══ MEAS ABSORB->CONC ═══╕ Select │
││ │ PQ cal range: │
││ Range 1: -> 0.5000AU │ │
││ Range 2: -> 0.7500AU │ │
││ Range 3: --- │ │
││ │ 1=Range 1 │
││ │ 2=Range 2 │
│└───────────────────────┘ 3=Range 3 │
└────────────────────────────────────────┘
Meas Absorb

Conc Range Select Display
In the above example, the calibration range from 0 to 0.1700 AU has one set of
calibration curve data (P,Q values) and the range from 0.1701 to 0.4000 AU has a second
set of calibration values. The reason for more than one set of calibration values is that the
first range may be relatively linear whereas the second range may be less linear. By
creating two separate ranges, the accuracy is significantly enhanced.
Select the desired range (1, 2, or 3). The Meas Absorb->Conc Parameter Select Display
appears (see. Meas Absorb

Conc Parameter Select Display, below).
┌────────────────────────────────────────┐
│╒═══ MEAS ABSORB->CONC ═══╕ │
││ │ │
││ Range 1: -> 0.1700AU │ │
││ │ │
││ Q= 2.06 │ │
││ P=-2.05 │ │
││ R= 0.00 │ │
│└───────────────────────┘ =Prev =Next │
└────────────────────────────────────────┘
Meas Absorb

Conc Parameter Select Display
The analyzer functions by measuring absorbance of light at the detector. Once the
absorbance is generated by the analyzer, it needs to be converted in concentration. To
accomplish this, the absorbance value is fitted into the following formula:
C = QA
2
+ PA + R
where:
C = Concentration of the chemical
Q = Quadratic parameter
P = Linear Parameter
R = Y-intercept (typically zero or very close to zero)
A = Absorbance
If in this example, the analyzer generates an absorbance value or 1.00, the following
concentration value is generated:
C = 2,043,480 (0.100)2 + 239,424 ((0.1) + 0.00
C = 20,434.80 + 23,942.40 = 44,377.20 ppb