• The problem to be solved:
  Measurement of chemical compounds in different environmental conditions

• Definition:
  Fibre optic photometer module with diode laser light source and semiconductor-based light absorbance measurement system. The analytical curve of the analyte, the parameters of the investigation and the condition variables are downloaded into microcontroller by a host computer. Several special sensing heads can be attached to the device to measure different compounds.

• Presentation:
  The device is mounted in 220 V powered, standard IP 65 house. PIC16 type microcontroller is applied to control the laser light source, to store the downloaded analytical curve, to calculate the results and to drive the liquid crystal display. The information can be transferred to the microcontroller by serial port of an IBM compatible PC. The device can be disconnected after downloading and can be used without PC. Optional possibility is ready to transfer the measured values back to the PC by serial port of the sensing device. The fibre optic cable of the laser and the detector can be attached in front of the system. The core of the fibre is high purity grade optical glass, the bundle is made from chemical resistive plastic. The end of the fibres are connected to the sensor head. This head contains a plate covered by sensing material. The cover consists of special compounds that absorb the laser light and could change colour depends on the concentration of the investigated analyte. The sensing compound could react with the analyte by chemical, physical and biological interactions. The light source is a diode laser with 20 mW output power and 635 nm wavelength. The measurement of light is performed by a high surface area silicium semiconductor detector. The proper temperature of the laser is supported by passive cooler. The coupling of the light signal is made by chemically resistive sapphire ball lenses. The laser is turned on by the microcontroller during the measurements. The sampling time is 1 second. After measurement of signal, the laser is turned off, and the background is measured. The absolute signal is calculated by microcontroller. This signal is proportional to the concentration of the analyte. Several parallel measurements are made. Immersing the sensor head into the gas or liquid stream, after the measurement the proper concentration value is displayed on the liquid crystal screen. The sensing head can be changed by using a simple fast - lock optical connector. The new parameters can be downloaded within several seconds. After it the device is ready to investigate a new compound in a new media.

The fibre optic detector module

• Application:
  Measurment of chemical compounds

• Advantages:
  Several different analytical curves and parameters can be stored by the host computer. Microcontroller device is flexible enough to handle the signals of different sensing modules and to calculate the results from environmental measurements. Application of modular system is very advantageous for investigation of more analytes in environmental on-field operations.

• Stage of development: Prototype of the device is ready. Sensor module for measurement of air humidity is ready. Sensor head for measurement of aromatic hydrocarbons is under development

• Documentation available: Yes
  

• Name(s): Dr. György BARKÓ and Dr. József Hlavay

• Self introduction:
  Dr. György Barkó: Bs. (Mechanical Engineering, 1990), Ms. (Chemical Engineering, 1992), Ph.D. (Environmental Sciences, 1997)
  Dr. József Hlavay: Ms. (Chemical Engineering, 1971), Ph.D. (Chemical Engineering, 1985), D.Sc. (Chemical Engineering, 1993)

• Form: Patent pending application, Utility model pending application
• Priority:
• Countries where it is force:

• Name: Dr. György Barkó, University of Veszprém
• E-mail: barkogy@almos.vein.hu
• Fax: +3688 - 423203
• Phone: +3688 - 422022 / 4698, +3620 - 9807627
• Address: H-8201 P.O.B. 158. Veszprém, Hungary