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Phosphonates
Interferences
Interfering Substance
Aluminum
Arsenate
Benzotriazole
Bicarbonate
Bromide
Calcium
CDTA
Chloride
Chromate
Copper
Cyanide
Diethanoldithiocarbamate
EDTA
Iron
Nitrate
NTA
Orthophosphate
Phosphites and
organophosphorus
compounds
Silica
Silicate
Sulfate
Sulfide
Sulfite
Thiourea
Highly buffered samples or
extreme sample pH
Sample Collection, Storage, and Preservation
Phosphonates
Page 4 of 6
Table 3 Interfering Substances and Suggested Treatments
100 mg/L
Interferes at all levels
10 mg/L
1000 mg/L
100 mg/L
5000 mg/L
100 mg/L
5000 mg/L
100 mg/L
100 mg/L
100 mg/L (Increase the UV digestion to 30 minutes.)
50 mg/L
100 mg/L
200 mg/L
200 mg/L
250 mg/L
15 mg/L
React quantitatively. Meta- and polyphosphates do not interfere.
500 mg/L
100 mg/L
2000 mg/L
Interferes at all levels
100 mg/L
10 mg/L
May exceed the buffering capacity of the reagents and require sample pretreatment.
The interference levels will decrease as the sample size increases. For example,
copper does not interfere at or below 100 mg/L for a 5.00 mL sample. If the
sample volume is increased to 10 mL, copper will begin to interfere above
50 mg/L.
Collect samples in acid-cleaned (1:1 HCl, Cat. No. 884-49) plastic or glass bottles
that have been rinsed with distilled water. Do not use a commercial detergent. If
prompt analysis is impossible, preserve the sample by adjusting to pH 2 or less
with Sulfuric Acid (about 2 mL per liter) (Cat. No. 979-49). Store at 4 °C (39 °F).
Preserved samples may be stored up to 24 hours. Correct the test result for
volume additions; see Section 3.1.3 Correcting for Volume Additions on page 29.
Interference Levels and Treatments
Phosphonates_PP_Other_PUV_Eng_Ody.fm
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