Hach DR2400 - Page 81

Aluminum
Aluminum
Aluminum_PP_Other_ECR_Eng_Ody.fm Page 3 of 6
Interferences
Polyphosphate interference can be reduced by converting polyphosphate to
orthophosphate by the following steps:
13. Touch Zero.
The display will show:
0.008 mg/L Al
3+
This test uses a non-zero
intercept for the
calibration curve.
14. Immediately wipe the
prepared sample and
place it into the cell
holder.
15. Touch Read.
Results will appear in
mg/L Al
3+
.
Interfering Substance Interference Levels and Treatments
Acidity Greater than 62 mg/L as CaCO
2
Alkalinity Greater than 750 mg/L as CaCO
3
Ca
2+
Greater than 1000 mg/L as CaCO
3
Cl
-
Greater than 1000 mg/L
Cr
6+
0.2 mg/L (error is -5% of reading)
Cu
2+
2 mg/L (error is -5% of reading)
Fe
2+
Greater than 4 mg/L (error is positive and = mg/L Fe
2+
x 0.0075)
Fe
3+
Greater than 4 mg/L (error is positive and = mg/L Fe
3+
x 0.0075)
F
-
See table on page 5.
Hexameta-phosphate 0.1 mg/L as PO
4
3-
(error is -5% of reading)
Mg
2+
Greater than 1000 mg/L as CaCO
3
Mn
2+
Greater than 10 mg/L
NO
2
–
Greater than 5 mg/L
NO
3
-
Greater than 20 mg/L
pH
2.9–4.9 or 7.5–11.5. A sample pH between about 4.9 and 7.5 causes dissolved aluminum to
partially convert to colloidal and insoluble forms. This method measures much of that
hard-to-detect aluminum without any pH adjusting pretreatment as is necessary in some other
methods.
PO
4
3-
(ortho) 4 mg/L (error is -5% of reading)
Polyphosphate See procedure below.
SO
4
2-
Greater than 1000 mg/L
Zn
2+
Greater than 10 mg/L
Zero
10 mL
Read