Hach DR2400 - Page 251

Copper
Copper
Copper_AVPP_Other_BIC_Eng_Ody.fm Page 3 of 6
Interferences
To differentiate free copper from that complexed to EDTA or other complexing
agents, use a Free Copper Reagent Powder Pillow in place of the CuVer 1
Powder Pillow in step 3. Results in step 8 will be free copper only. Add a
Hydrosulfite Reagent Powder Pillow to the same sample and re-read the result.
This result will include the total dissolved copper (free and complexed). Unlike
CuVer 1 Reagent, CuVer 2 Reagent Powder Pillows and AccuVac Ampuls react
directly with copper, which is complexed by chelants such as EDTA.
5. Touch the timer icon.
Touch
OK
A 2-minute reaction
period will begin.
6. When the timer
beeps, place the blank
into the cell holder. Close
the cover.
7. Touch Zero.
The display will show:
0.00 mg/L Cu
8. Within 30 minutes
after the timer beeps,
place the AccuVac Ampul
into the cell holder.
Touch
Read.
Results will appear in
mg/L Cu.
10 mL
20 mL
25 mL
Zero
Table 1 Interfering Substances and Suggested Treatments for Powder Pillows
Interfering Substance Interference Levels and Treatments
Acidity
If the sample is extremely acidic (pH 2 or less) a precipitate may form. Add 8 N Potassium
Hydroxide Standard Solution (Cat. No. 282-32H) drop-wise while swirling to dissolve the
turbidity. Continue with step 2.
Aluminum, Al
3+
Follow the powder pillow procedure above, but substitute a CuVer 2 Copper Reagent Powder
Pillow (Cat. No. 21882-99) for the CuVer 1 Pillow used in step 3. Results obtained will include
total dissolved copper (free and complexed). Requires a 25-mL sample cell.
Cyanide, CN
–
Prevents full color development. Before adding the CuVer 1 Powder Pillow Reagent, add 0.2 mL
of formaldehyde (Cat. No. 2059-32) to the 10-mL sample. Wait 4 minutes before taking the
reading. Multiply the test results by 1.02 to correct for sample dilution by the formaldehyde.
Hardness
Follow the powder pillow procedure above, but substitute a CuVer 2 Copper Reagent Powder
Pillow (Cat. No. 21882-99) for the CuVer 1 Pillow used in step 3. Results obtained will include
total dissolved copper (free and complexed). Requires a 25-mL sample cell.
Iron, Fe
3+
Follow the powder pillow procedure above, but substitute a CuVer 2 Copper Reagent Powder
Pillow (Cat. No. 21882-99) for the CuVer 1 Pillow used in step 3. Results obtained will include
total dissolved copper (free and complexed). Requires a 25-mL sample cell.
Silver, Ag
+
If a turbidity remains and turns black, silver interference is likely. Add 10 drops of saturated
Potassium Chloride Solution (Cat. No. 765-42) to 75 mL of sample, followed by filtering through
a fine or highly retentive filter. Use the filtered sample in the procedure.