Robust optical absorbance probe for titration and photometry is designed as a replacement for ion selective electrodes used as end-point sensors in complexometric determinations of metals
This optical sensor allows automation of colorimetric titration and can also double as liquid level sensor.
Its novel optical window eliminates air bubble entrapment and ensures trouble free unattended operation, says Chemro.
FotoSense is designed as a replacement for ion selective electrodes used as end-point sensors in complexometric determinations of metals.
It consists of three components: sensor head with interconnect cable, electronics module, and power unit.
The sensor head is a patented construction containing light source, detector and pre-amplifier in a standard 12mm diameter 120mm long shaft.
All parts are potted in epoxy.
The probe is essentially a single mass with no seals as with the optical windows of conventional probes.
This ensures that the probe cannot develop any leak, exposing the opto-electronics to corrosive chemistry.
The integrated light source is a modern high intensity and robust LED.
These are know for their long life of up to 100,000 hours.
The optical concept is a single pass of the sample and employs a novel angled window that prevents collection of air bubbles when the sensor is dipped into the sample or when the measuring vessel is filled.
This is important for automated analysis.
Because of the sensor's special angled window, the probe experiences total internal reflexion of the light beam when it is not immersed in an the sample.
Thus when the sensor is held in air, only a limited amount of light will emerge from the window.
The output signal is then low.
As the angled window becomes covered with sample, light transmission to the detector occurs and the signal jumps to the normal values.
This feature can be used effectively for liquid level detection and therefore also for automating the filling of the analysis vessel.
The LED light source is driven from a switched supply in the kHz range and the signal processing electronics registers only the components from the detector at the switching frequency.
This assures that the sensor is essentially free from ambient light interference.
FotoSense is chemically inert and provides general detection capabilities where often no suitable ion selective electrode exists.
Dip probe sensor for photometric titrations and measurements.
Ambient light cancelling electronics.
Standard 12mm diameter shaft 120mm length in high grade engineering plastic (Ryton).
Four standard wavelengths available: 470, 520, 590, 630nm (others to special order).
Output signal compatible with standard laboratory equipment (0-2000mV variable range).
BNC output connector.
Low voltage (5V) supply from standard adapter (other input voltages available on special order).
No contamination or poisoning effects as with ISEs.
Use as liquid level sensor.
Max operating temperature 95C.
Optical path length approx 10mm.
