Ocean Optics OOISensors - Manual (Page 70)

4: pH Sensors
Note
Be careful not to over-tighten the tip. Over-tightening the tip can break the mirror in the
transmission probe or break the film in the reflection probe.
6. Place the probe in the first pH sample, ensuring that there are no bubbles in the light path of the
probe (only applicable to transflectance probes).
pH Sensors Analysis Wavelengths
Indicator Film
Valid pH
Range
Isobestic
Wavelength
(nm) HA Peak
Wavelength
(nm) A Peak
Wavelength
(nm)
Baseline
Wavelength (nm)
Phenol Red 6.5 – 8.5 470 435 575 750
Cresol Red 8.0 – 10.0 490 424 587 750
m-Cresol Purple 8.5 – 10.5 487 435 593 800
Thymol Blue 9.0 – 12.0 495 440 605 800
Brilliant Yellow 7.0 – 9.0 465 412 523 700
60 FOXY-AL300-000-02-0207