Hach DR/850 - Page 81

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Perform the bromine analysis immediately after collection.
Accuracy Check
Standard Additions Method (using powder pillows)
a) Snap the top off a LR Chlorine PourRite
®
Ampule Standard
Solution.
b) Use a TenSette Pipet to add 0.1 mL of the standard to the
reacted sample (this is the spiked sample). Swirl to mix.
c) Re-zero the instrument using the original sample (the
blank).
d) Place the spiked sample in the cell holder and press
READ.
Record the result.
e) Calculate the equivalent concentration of mg/L bromine
added to the sample:
f) The spiked sample result (step d) should reflect the
analyzed sample result + the calculated mg/L Br
2
added
(step e).
g) If this increase does not occur, see Standard Additions in
Section 1 for more information.
Standard Additions Method (using AccuVac Ampuls)
a) Snap the top off a LR Chlorine PourRite Ampule Standard
Solution.
b) Use a graduated cylinder to measure 25 mL of sample into
each of two beakers.
c) Use a TenSette Pipet to add 0.2 mL of the standard to one
of the beakers (this is the spiked sample). Swirl to mix.
d) Fill a DPD Total Chlorine AccuVac completely from each
beaker.
e) Analyze the spiked and unspiked sample as described in
the procedure.
f) Calculate the equivalent concentration of mg/L bromine
added to the sample:
mg/L Bromine added
0.1 (vol. standard added) Label value (mg/L Chlorine)× 2.25×
10.1 (sample + standard volume)
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BROMINE, continued