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 The Fiber Optic pH Sensor system consists of a fiber
optic probe designed to hold immobilized colorimetric indicator dye
materials, plus a light source, spectrometer and OOISensors
Software. You can supply your own indicator material, or select from
our line of transparent or reflective films. Calibration involves
recording spectra in high and low pH samples, and in at least one pH
standard such as a NIST-traceable buffer.
Transmissive and Reflective pH Films
Transmissive films are for clean, transparent samples. These films
consist of a cellulose mechanical matrix surrounded by a hydrophilic
polymer that entraps the indicator dye. Reflective films are used for
turbid or absorbing media.
Film Performance
When immersed in water, the film dyes may leach very slowly over time
and will have to be replaced. The film response rate is slow (on the order
of minutes), being limited by diffusion of ions into the material.
Increasing stirring speed, ionic strength and temperature all tend to
increase the response rate and do not affect the pH measurement. Nearly
any aqueous sample environment is suitable, as are some solvents.
TP300 Probe
The TP300-UV-VIS Probe is a chemically inert PEEK
transmission probe that can be equipped with a tip for mounting transmissive films in
the optical path. Light is directed via one fiber through the mounted film
to a mirror. Then light is redirected back through the film to a receive
fiber that returns the light to the spectrometer. The sample is free to
flow over the sides of the film. By using an RTP-2-10 (adjustable 2-10 mm)
Transmission Tip, the TP300-UV-VIS can be used for routine transmission
measurements.
Note: Only recommended for use with
spectrometers with 50 µm slits.
TP300-UV-VIS: Call for Price
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Item |
Specification |
|
Fiber type |
(2) 300 µm
core diameter fibers (1 illumination, 1 read) |
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Outer diameter: |
3.175
mm |
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Length: |
107.9
mm for probe, 2 meters for fiber |
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Optics: |
Fused
silica |
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Internal materials: |
Aluminum |
|
Pressure: |
100
psi |
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Pathlength: |
16 mm
with RT-PH Tip |
|
Outer materials: |
PVC
fiber jacketing, PEEK polymer for sleeve |
|
Connector: |
SMA
905 |
|
Operating temperature: |
Up to
220º C with PEEK sleeve |
RF200 Probe
The RFP200-UV-VIS Reflective Film Probe consists of a 6-around-1 fiber
bundle in a chemically inert 6.35-mm OD Torlon body. The open tip of the
probe screws onto the body to hold 3.17-mm to 4.76-mm discs of reflective
indicator material. The 6-fiber leg attaches to the light source; the
central fiber leg connects to the spectrometer. The sample has access to
the sensing material from one side only.
RFP200-UV-VIS: Call for Price
Transmissive Indicator Dye Films for pH Sensing
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Item |
Film Type |
pH Range |
Color Change
|
|
PH-BCG-TRANS |
Bromocresol green |
5.0-9.0 |
Yellow-Blue |
No Resale
The goods identified herein are subject to the condition that they
shall not, nor any portion of them, by way of trade or otherwise, be
lent, resold, or otherwise conveyed to a subsequent borrower, purchaser,
or transferee unless Purchaser has a currently valid License,
Distribution, or Sales Representative Agreement expressly granting
permission to so convey the goods. Please contact our sales department
if you are interested in obtaining a license.
pH
References
Spectrophotometric
Determination of Freshwater pH Using Bromocresol Purple and Phenol Red.
Author: Yao, Wensheng; Byrne, Robert H. Source: Environmental Science and
Technology v. 35 no6 (Mar. 15, 2001) p. 1197-201
Spectrophotometric Determination of
Seawater pH Using Phenol Red. Author: Robert-Baldo, Gillian L.; Morris,
Michael J.; Byrne, Robert H. Source: Analytical Chemistry v. 57 (Nov.
1985) p. 2564-77
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