64
METHOD PROCEDURES
64
64
OZONE
• To determine the
mg/L ozone (O
3
)
concentration in sample containing chlorine, subtract value B
(additional measurement procedure) from value A (standard measurement procedure).
INTERFERENCES
Interference may be caused by:
• Bromine, Chlorine Dioxide, Iodine
• Hardness greater than 500 mg/L CaCO
3
, shake the sample for approximately 2 minutes after
adding the powder reagent
• Alkalinity above 250 mg/L CaCO
3
will not reliably develop the full amount of color or it may rapidly
fade, neutralize the sample with diluted HCl.
• If the sample is suspected to contain chlorine residue (free or total chlorine), follow the alternative
measurement procedure described below, chlorine is a strong interferent.
1. Perform the Standard Measurement Procedure. Record the result as Value A.
2. Perform Additional Measurement Procedure. Record the result as Value B.
3. To determine the ozone concentration in mg/L, subtract Value B from Value A.
mg/L ozone (O
3
) = Value A – Value B