• Rapid measurements of dissolved hydrogen peroxide.
• Calibrated and ready to use.
• Ideal for solutions with depths less than 1m.
• Data loggers available, if required.

 

The amperometric H₂O₂ micro-sensor has been developed for the in-situ determination of H₂O₂-containing aqueous solutions. Compared to all the other commercially available H₂O₂ measuring systems and to permanganate and iodometric methods the new micro-sensor has some advantages, such as high economy, low detection limits, low analyte consumption and fast response times. Streaming, as it is well-known from all membrane-covered sensors, is not necessary.

The laboratory sensor with integrated electronic device contains an exchange sensor tip to allow an exchange between H₂O₂, H₂S and O₂ sensor tips.

 

the laboratory model sensor

This sensor has been developed for the laboratory and simple field use and must be combined with one of the offered measuring instruments. The sensor consists of a titanium housing, a water-proof connection with the cable (IP 68), an exchangeable sensor head and a removable protection cage (on your own risk - no guarantee in the case of mechanical destruction).

This sensor could be equipped both with the following sensor tips: hydrogen peroxide sensor tip type I (0,02…10% H₂O₂). The exchange of the sensor head is very easy by pull off and push on.

 

determination of dissolved hydrogen peroxide in aqueous solutions

The amperometric H₂O₂ micro-sensor has been developed for the in-situ determination of hydrogen peroxide containing aqueous solutions. Therefore, the sensor is suitable for direct measurements in coloured and turbid solutions (wastewater), in industrial plants, but also in biological research.

Compared with all the other commercially available hydrogen peroxide sensors, this amperometric H₂O₂ micro-sensor works with such a low analyte consumption, that streaming of the sensor membrane or stirring of the analyte is not necessary. And, an additional stirrer is not necessary for stationary measurements.

The second advantage of the micro-sensor is the very fast response time with t90% =1-2 seconds.

The third advantage of the new micro-sensor is based on the microsensor technology itself. High signal stability, high local signal resolution allows some new applications, as for instance the profiling in μm-steps.

 

the general working principle of the sensor

Because of the partial pressure of the gaseous H₂O₂ dissolved in the sample, the analyte is separated from the inner electrolyte by means of the membrane. The membrane is only pervious to gases, so that liquids, ions and solids are not able to reach the inner electrolyte or the electrodes of the sensor.

The sensor contains inside a special electrolyte and 3 electrodes. The electrode materials have been selected and prepared very carefully to realize ideal electrochemical conditions. The time for the polarization, realized by means of the sensor’s integrated electronic device, is approximately 5…15 minutes after the first switching on or long breaks.

If the H₂O₂ has passed now the membrane, it reacts chemically with the redox catalyst and forms a new compound. After this, this compound is transported by diffusion to the working electrode followed by the electrochemical reaction. This causes a current depending on the hydrogen peroxide partial pressure/hydrogen peroxide concentration of the sample.

The observed current within a range of 0...400 picoamperes is converted into a voltage of 0...5 Volt inside the integrated electronic device of the sensor.

Besides, in opposite to other measuring principles, the current flow in the amperometric sensor leads to a rapid decrease of the analyte inside the sensor resulting in very fast response times even though there is a concentration jump from high to low concentrations.

All commercially available electrochemical sensors must be combined with a temperature measurement and the amperometric H₂O₂ sensor too. When ordering a multi-sensor measuring system for laboratory use or a complete submersible probe system, the temperature measurement and the temperature correction of the sensor signal is already included. If measurements in a flow through system are required, special temperature sensors for the integration in flow through cells are offered. When measuring in opened vessels or beakers in the laboratory, the customers must realize the temperature measurement themselves. If a calibrated sensor is ordered, the temperature correction is very easy by means of a factor or for more accurate measurements by means of a mathematical formula, delivered with the sensor.