DR/2400
Silica
Silica_PT_ULow_HTB_Eng_Ody.fm Page 1 of 6
• Reagent blank values printed on analyzer reagent containers vary because the reagents’ dilutions vary according to instrument.
For this method, use the 1234D analyzer reagent blank value for a 3.78 L volume of Molybdate 3 Reagent (Cat. No. 1995-17).
For a Series 5000, 2.9 L volume of Molybdate 3 Reagent (Cat. No. 1995-03), multiply the reagent blank on the label by 1.09.
For 100-mL Molybdate 3 Reagent (Cat. No. 1995-32) and 1 L Molybdate 3 Reagent (Cat. No. 1995-53), use the lab blank values
on the bottle labels.
• The four-minute reaction time in step 11 is for samples at 20 °C; for samples at 10 °C, wait eight minutes;
for samples at 30 °C, wait two minutes.
• The one-minute reaction time in step 13 is for samples at 20 °C; for samples at 10 °C, wait two minutes;
for samples at 30 °C, wait 30 seconds.
• Clean labware carefully. See Labware on page 4.
• Use only plastic containers and labware; glass can contaminate the sample.
• Install the Pour-Thru Cell into the adapter so that the long pathlength (1-in./25-mm) is parallel to the front of the instrument.
Silica
Method 8282
Heteropoly Blue Method*
*Adapted from Standard Methods for the Examination of Water and Wastewater.
Pour-Thru Cell
ULR (3 to 1000 µg/L as SiO
2
)
Scope and Application: For testing trace levels of soluble silica in pure and ultrapure water
1. Touch
Hach Programs.
Select program
645 Silica ULR.
Touch
Start.
2. Account for the
Molybdate 3 reagent
blank by touching
Options, then Reagent
Blank
. Touch On.
3. To adjust the reagent
blank value, touch the
existing value and adjust
it with the numeric
keypad. Touch
OK,
Adjust, and Return.
4. Install the Pour-Thru
Cell and cell adapter in
the sample cell
compartment.
Note: See Section 2.6.1 on
page 26 in the Instrument
manual for installation details.
Flush with 50-mL of
deionized water.
Note: Use the 25-mm cell
pathlength.
Tips and Techniques
DR/2400 Pour-Thru Cell Method 8282
Hach Programs
Reagent Blank:
0.2
Options
On
OK
Return
Adjust
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