Ocean Optics pH Sensor Patches, Probes and Cuvettes - Manual (Page 13)

1: Products
PHSENSOR-TRANS-REFLECT-201111 7
2. Continue streaming jets of liquid onto the patch until the entire backside looks uniformly dark
and wet. This only needs to be done initially; once the mesh has been wetted, there is free and
fast diffusion of ions in and out of the sensor material.
Storage/Lifetime
Patches can be stored dry at room temperature for any amount of time. As a rule, once the maximum
absorbance at pH 11 falls below 0.1, the patch should be discarded and replaced (assumes a
reference of pH 1). The patch’s lifetime depends on frequency of use, harshness of the samples it is
exposed to, the temperature of samples, and other environmental factors.
Performance Specifications
Specification Ocean Optics pH Probe Value
pH range 4 – 9
Analytical Wavelength 617nm
Baseline Correction Wavelengths 509nm (isosbestic) or 800nm
Calibration Options User Calibration with 6 Buffers
Factory Calibration with 3 Buffers
Immediate Startup with No Buffers (requires undisturbed setup)
Typical Absorbance Range 0.12 – 0.25
Typical pK Range 6.1 – 6.5
Typical Slope Range 2.2 – 3.0
User Calibration Accuracy Up to 2% of reading
Factory Reset Accuracy 0% at reset point
1% Within 1 pH unit of reset
Up to 4% at 3 pH units from reset
Resolution About 0.03 pH unit in most cases (determined by distance of
optics, probe type, and age of patch)
Response Time, t
(90)
30 seconds (determined by salinity of sample and liquid flow at
sensor interface)
Stability No detectable drift for up to 12 hours
1% per day for long term monitoring
Interferences Strong green or blue sample color may cause up to 0.25 pH unit
increase