Molybdenum, Molybdate
Molybdenum, Molybdate
Page 2 of 6
Molybdenum_PP_Low_TER_Eng_Ody.fm
Interferences
Interferences studies were conducted by preparing a molybdenum standard
solution (2-mg/L Mo
6+
) as well as a solution of the potential interfering ion.
When the standard solution concentration changed by ±5% with a given ion
concentration, the ion was considered an interference. The tables below list the
details of these studies.
9. Wipe the blank and
place it into the cell
holder.
10. Touch Zero.
The display will show:
0.00 mg/L Mo
6+
11. Wipe the developed
sample and place it into
the cell holder.
12. Touch Read.
Results will appear in
mg/L Mo
6+
.
10 mL
Zero
10 mL
Read
Table 1 Substances that Cause a Negative Interference
Interfering Substance Interference Levels and Treatments
Alum Greater than 7 mg/L
Aluminum Greater than 2 mg/L
AMP (Phosphonate) Greater than 15 mg/L
Bicarbonate Greater than 5650 mg/L
Bisulfate Greater than 3300 mg/L
Borate Greater than 5250 mg/L
Chloride Greater than 1400 mg/L
Chromium Greater than 4.5 mg/L*
Copper Greater than 98 mg/L
Diethanoldith-iocarbamate Greater than 32 mg/L
EDTA Greater than 1500 mg/L
Ethylene Glycol Greater than 2% (by volume)
Iron Greater than 200 mg/L
Lignin Sulfonate Greater than 105 mg/L
Nitrite Greater than 350 mg/L
Orthophosphate Greater than 4500 mg/L
Phosphonohydroxyacetic
Acid
Greater than 32 mg/L
HEDP (Phosphonate)
The presence of the phosphonate HEDP at concentrations up to 30 mg/L will increase the
apparent molybdenum concentration reading by approximately 10% (positive interference).
Multiply the value obtained in step 12 by 0.9 to obtain the actual Mo
6+
concentration.
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