Smart Cuvettes Instructions
2 SC-PH-VIS1M-SAM-01-1109
Cuvette Storage/Lifetime
Smart Cuvettes can be stored dry at room temperature for any amount of time. As they are used, the
cuvettes may slowly leach indicator dye from the sensing material. As a rule,
once the maximum
absorbance at pH 11 falls below 0.1, the cuvette should be discarded and replaced
(assumes a
reference of pH 1). The cuvette’s lifetime depends on frequency of use, harshness of the samples it is
exposed to, the temperature of samples, and other environmental factors.
Nature of Samples
The analyte solutions being measured should have a pH within the biological range (pH 5-9) for
accurate readings. Data obtained from analyte solutions that register values above or below this range
should not be considered valid within the specifications of the cuvette. Concentrated acids and acetone
will ruin the plastic cuvettes, so these types of chemicals should be avoided. Aqueous solutions,
ethanol/methanol solutions, peroxides, ammonia, and sodium hypochlorite solutions are all compatible
with the sensor material and the plastic cuvette. Samples should be optically transparent, having no
turbidity or sediment present. It is also ideal to have analyte solutions that are colorless, though
colored liquids can be compensated for.
Response time is dependent on the ionic strength of the solution, with higher salinity samples
responding notably faster. For example, using the calibration buffers of pH 5 – 8 will show a 90%
response in 10 seconds or less, but when pure D.I. water is being measured, more time is needed to
equilibrate at a final value. Make sure that the cuvette is filled to a sufficient level with the analyte
solution. If the liquid level is at or below the optical path, the data will not be valid. To ensure there is
sufficient liquid, it is recommended to fill the cuvette about 70% its height. Likewise, more accurate
results will be obtained if the cuvette is rinsed once or twice with the analyte solution after calibration.
This removes any residual buffer solution that may contaminate your sample. Note that once the
cuvette has been affixed into the cuvette holder, it should not be moved or removed until all
measurements have been completed.
When immersed in solution, the film dyes may leach very slowly over time and will have to be
replaced. The film response rate is limited by diffusion of ions into the material, therefore increasing
stirring speed and ionic strength tend to increase the response rate.
pH Smart Cuvette Set Up
The following procedures describe how to connect and calibrate pH Smart Cuvettes using a VIS-NIR
spectrometer, a light source and SpectraSuite software. See your spectrometer and SpectraSuite
manual for more detailed installation information.
Installing the pH Sensor System
► Procedure
Perform the steps below to install the pH Sensor components:
1. Install SpectraSuite on your computer.
2. Connect the spectrometer to your computer using the supplied USB cable.
3. Install the light source as specified in its instructions.
