42-4
BENZOTRIAZOLE AND TOLYLTRIAZOLE, continued
13. Press: ZERO
The display will
count down to 0.
Then the display will
show 0.00 mg/L and
the zero prompt will
turn off.
14. Place the
prepared sample in
the cell holder.
Note: In bright sunlight
it may be necessary to
close the cell
compartment cover.
15. Press: READ
The display will
count down to 0.
Then the display will
show the results in
mg/L benzotriazole
or tolyltriazole.
SAMPLING AND STORAGE
The most reliable results are obtained when samples are analyzed as
soon as possible after collection.
ACCURACY CHECK
Standard Additions Method
a) Use the TenSette Pipet to add 0.1, 0.2 and 0.3 mL of standard
solution, 500 mg/L benzotriazole, to three 25-mL samples. Perform the
test according to the above procedure.
Note: The test will not distinguish between benzotriazole and tolyltriazole.
b) Each addition of 0.1 mL of standard solution should increase the
benzotriazole reading by 2 mg/L over the reading of an unspiked sample.
c) If these increases are not obtained see Standard Additions (Section I)
for more information.
UV Lamp Check
To verify the ultraviolet lamp (normal life equals 5000 hours) is working
properly, perform the following test:
a) Prepare a 5.0 mg/L benzotriazole standard solution by pipetting
10.0 mL of benzotriazole standard solution, 500 mg/L benzotriazole,
into a 1-L volumetric flask. Dilute to volume.
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