LaMotte SMART3 Colorimeter - Manual (Page 246)

APPLICATION: Drinking, surface, and saline waters, swimming pool
water; domestic and industrial wastes.
METHOD: The various pH indicators exhibit a specifi c color
change over a narrow pH range. The color changes are
measured colorime trically.
SAMPLE HANDLING
& PRESERVATION:
Sample should be analyzed immediately after collection.
INTERFERENCES: Sample color and turbidity interfere with the colorimetric
pH measurement. Color interference may be removed
bystandardizing the instrument with the original water
sample. Two drops of 0.1N sodium thiosulfate per 100
mL of sample will eliminate chlorine interference.
INDICATOR, RANGE,
& TEST NAME:
pH Indicator pH SMART3 Test Name
Chlorphenol Red 5.0-6.8 073 pH CPR
Phenol Red 6.6-8.4 074 pH PR
Thymol Blue 8.0-9.6 075 pH TB
pH SMART3 Test Procedures 11.10
Test P
rocedures