Chromium, Hexavalent
Chromium, Hexavalent
ChromiumHex_AVPP_Other_DCH_Eng_Ody.fm Page 3 of 6
Interferences
Sample Collection, Preservation, and Storage
Collect samples in a cleaned glass or plastic container. Store at 4 °C (39 °F) up to
24 hours. Samples must be analyzed within 24 hours.
Accuracy Check
Standard Additions Method (Sample Spike)
1. After reading test results, leave the sample cell, or AccuVac Ampul
(unspiked sample) in the instrument. Verify the chemical form.
2. Touch
Options. Touch Standard Additions. A summary of the standard
additions procedure will appear.
3. Touch
OK to accept the default values for standard concentration, sample
volume, and spike volumes. Touch
Edit to change these values. After values
are accepted, the unspiked sample reading will appear in the top row. See
Standard Additions in the instrument manual for more information.
4. Snap the neck off a Chromium Voluette
®
Ampule Standard, 12.5 mg/L Cr
6+
.
5. Touch the timer icon.
Touch
OK.
A five-minute reaction
period will begin.
6. When the timer
beeps, place the blank
into the cell holder.
7. Touch Zero.
The display will show:
0.00 mg/L Cr6+
8. Place the prepared
sample into the cell
holder.
Touch
Read.
Results will appear in
mg/L Cr
6+
.
Interfering Substance Interference Levels and Treatments
Iron May interfere above 1 mg/L
Mercurous & Mercuric Ions Interfere slightly
pH
Highly buffered samples or extreme sample pH may exceed the buffering capacity of the
reagents and require sample pretreatment. See Section 3.3 Interferences on page 41.
Vanadium May interfere above 1 mg/L. Allow 10 minutes for the reaction period before reading.
Tu rb i di ty
For turbid samples, treat the blank with the contents of one Acid Reagent Powder Pillow
(Cat. No. 2126-99). This will ensure that any turbidity dissolved by the acid in the ChromaVer 3
Chromium Reagent will also be dissolved in the blank.
10 mL
Zero
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