FIAlab Instruments, Inc.
14450 NE 29th Place STE 113
Bellevue, WA 98007 USA
Voice: 425-376-0450
Fax: 425-376-0451
fialab@flowinjection.com
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FIAlab standard method for sulfate assay
using the
FIAlab-2500/2600/2700 system.
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Assay |
Typical Throughput |
Concentration Range |
Notes |
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Sulfate (Mid-high) |
120 samples/hour |
1 to 50 mg Cl-/L |
1 cm flowcell |
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Sulfate (Low) |
60 samples/hour |
0.1 to 5 mg Cl-/L
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10 cm flowcell |
Principle:
Sulfate in the sample is
precipitated with acidified barium chloride.
This precipitate
scatters light producing a signal proportional
to sulfate concentration.
The following
method should work for concentrations from 10
ppm to 200 ppm.
Please inquire for
suggestions on how to measure lower or higher
concentrations than these ranges.
Comments:
For most Sulfate assays make the sample loop from 12 inches of
0.03" ID tubing.
Use a 10 cm flowcell for
concentrations of 10 ppm to 200 ppm.
Use a 1 cm flowcell for
concentrations consistently greater than
100 ppm.
Recommended monitored wavelength
is 500 nm, though any wavelength from
400 to 800 nm will work.
Do not use a reference
wavelength.
Sulfur can be
added to the reagent to “seed” the
precipitate.
This is necessary for the lower
concentrations.
Interferences:
Color and suspended
particulates will interfere. Sulfites
and sulfides may oxidize and then
precipitate as barium sulfate. Large
quantities of organic matter interfere.
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Reagents:
Carrier: Matrix Match
Matrix Match.
If samples are water then use
water as carrier.
If soil extract, then (typically)
add KCL in proportion with the extracted
samples, e.g., 12 g KCL per liter of
water.
The matrix matching isn’t
critical if samples have greater than
100 ppm Sulfate concentration.
Reagent 1: Barium Chloride + HCL +
Sulfur (for one liter)
30.0 grams
BACl
Dihydride
10 ml
Hydrochloric acid
0.004 grams
Sulfur of DI Water
(this is not needed for sample sulfate
conc. > 10 ppm)
1-Liter
DI Water.
Stir
until dissolved.
Reagent 2: No Reagent 2 –
plug this channel port
Standards:
100ml
ICSUL-100 (Sulfate standard)
Source:
727-524-7732 -
www.exaxol.com
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Please email or phone FIAlab Instruments
for additional product information.
Email:
fialab@flowinjection.com,
Voice: 425-376-0450 or 1-800-963-1101,
Fax: 425-376-0451
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