Chemical Analysis
Chemical Analysis
Page 46
5940022ChemAnal.fm
Figure 12 Semilogarithmic Calibration Curve
To convert %T readings to concentration, prepare a table such as Table 9 and
select the appropriate line from the “%T Tens” column and the appropriate
column from the “% T Units” columns. The %T Ten value is the first number of
the % transmittance reading and the %T Units value is the second number of the
% transmittance reading. For example, if the instrument reading was 46%, the 40
line in the %T Tens column and the 6 column in the %T Units would be selected.
The cell where these two intersect (0.78 mg/L) is the iron concentration of the
sample.
2.40
1.60
1.80
0.40
2.00
0.20
2.20
0.00
10
20
30
40
50
60
80
100
0.60
1.40
1.20
1.00
0.80
PERCENT TRANSMITTANCE
mg/L IRON
Table 9 Calibration Table
Absorbance Units
Absorbance
Tens
0123456789
0 ––––––––––
10 2.30 2.21 2.12 2.04 1.97 1.90 1.83 1.77 1.72 1.66
20 1.61 1.56 1.51 1.47 1.43 1.39 1.35 1.31 1.27 1.24
30 1.20 1.17 1.14 1.11 1.08 1.04 1.02 .99 .97 .94
40 .92 .89 .87 .84 .82. .80 .78 .76 .73 .71
50 .69 .67 .65 .64 .62.60.58.56.55.53
60 .51 .49 .48 .46 .45.43.42.40.39.37
70 .36 .34 .33 .32 .30.29.28.26.25.24
80 .22 .21 .20 .19 .17.16.15.14.13.12
90 .11 .09 .08 .07 .06.05.04.03.02.01
To Next Page
Loading...
