Waltron AQUALERT Aqualyzer 3051, Инструкция по эксплуатации

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Introduction
17
Waltron User Manual
3051 Hardness Analyzer
Absorbance for liquids is defined as the negative logarithm of the transmittance:
A = - log
10
T = log
10
1 / T = log
10
I
0
/ I
1
I
0
= light intensity through the sample before colorimetric reaction
I
1
= light intensity through the sample after colorimetric reaction
In most cases the absorbance has a linear correlation with the sample concentration; for a linear
calibration line just the blank and span values (i.e. concentration with zero analyte and the
maximum expected concentration) are needed. Multiple analysis at each point that are averaged
will provide a more accurate calibration line.
The absorbance ranges from 0 to 1, but it can go higher than that.

An absorbance of 0 at some wavelength means that no light of that particular wavelength
has been absorbed. The intensities of the sample and reference beam are both the same, so
the ratio I
0
/I
1
is 1. Log
10
of 1 is zero.

An absorbance of 1 happens when 90% of the light at that wavelength has been absorbed
which means that the intensity is 10% of what it would otherwise be. In that case, I
0
/ I
1
is
100/10 (=10) and log
10
of 10 is 1.
Absorption photometry (Colorimetry):
The methods used are based on the formation of a colored complex of the analyte with a color
reagent. Light with a specific wavelength is send through the reaction mixture. The absorbance
of this light by the formed complex, measured by a photometer, is related to the concentration of
the analyte.
reading sensor
reference
Absorbance log

Figure 2.3: Color development.