Hach 1950Plus - Page 51

Section 3
Page 51
UVTOCReagents and Standards.fm Preparing Phosphoric Acid Solution
Caution: Always pour the
concentrated acid into the water;
never pour water into the acid.
Take the same precautions you
would normally take when
handling any corrosive material.
See Safety Note 7 on page 185 for
Spanish, French, German, or
Italian translations.
The ideal sample pH after addition of acid is 3.0 or less, for efficient removal
of inorganic carbon. In some cases, stronger solutions and/or higher pumping
rates may be required to adequately maintain the pH of the sample in the TIC
scrubber. Determine the necessary acid reagent concentration by adding
phosphoric acid to a sample until the pH is reduced to 3.0 or less. To verify the
pH is 3.0 or less, collect a sample from the drain line.
Table 7 details the concentration of acid required to remove 10 mg/L and 100
mg/L C as TIC for each analyzer. Select the appropriate molarity to remove
the anticipated TIC in your sample.
Table 7 Reagent Tables
UV 4195- / 6195-
1010/
3010
1020/
3020
1030/
3030
1040/
3040
1050/
1050
1060/
3060
1070/
3070
2000/
4000
TOC Range mg/L 5 10 25 50 100 200 500 100
Sodium Persulfate
Molarity 0.2 0.4 0.6 0.6 0.4 0.5 0.6 0.7
g per 20 L 950 1900 2860 2860 1900 2380 2860 3330
Usage days per 20 L 90 90 90 90 90 90 90 30
Phosphoric Acid
TIC mg/L C (Na
2
CO
3
) 10 100 10 100 10 100 10 100 10 100 10 100 10 100 10 100
Molarity 0.1 0.6 0.1 0.6 0.1 0.6 0.05 0.3 0.02 0.1 0.02 0.1 0.02 0.1 0.1 0.6
mL (85% H
3
PO
4
) per
20 L
137 819 137 819 137 819 68 410 27 137 27 137 27 137 137 819
Usage days per 20 L 30 30 30 30 30 30 30 30
UV 4195-
2010/
4010
2020/
4020
2030/
4030
2040/
4040
2050/
4050
2060/
4060
2070/
4070
2080/
4080
TOC Range mg/L 200 500 1000 1000 2000 5000 10000 20000
Sodium Persulfate
Molarity 1.4 1.6 0.9 0.9 1.5 1.2 0.9 1.2
g per 20 L 6660 7620 4280 4280 7140 5710 4280 5710
Usage days per 20 L 30 30 30 30 30 30 30 30
Phosphoric Acid
TIC mg/L C (Na
2
CO
3
) 10 100 10 100 10 100 10 100 10 100 10 100 10 100 10 100
Molarity 0.1 0.6 0.04 0.3 0.04 0.3 0.04 0.1 0.02 0.1 0.02 0.1 0.02 0.1 0.02 0.1
mL (85% H
3
PO
4
) per
20 L
137 819 55 410 55 410 55 137 27 137 27 137 27 137 27 137
Usage days per 20 L 30 30 30 30 30 30 30 30