Portable Meters

Portable meters are available with probes that use either the Clarke-Type Polarographic, Galvanic, or Optical technologies. The portable meters include those with manual calibration and manual selection of altitude and salinity compensation values. Portable meters also include versions that have a barometric pressure transducer for automatic pressure compensation along with versions that have an EC sensor for salinity compensation. Meters are available with the BOD, OUR and SOUR programs built-in for automatic calculation.

Portable Meters with Polarographic Probe

The following portable meters use Clark-Type Polarographic probe. Polarographic DO probes consist of a working electrode (cathode) and a counter electrode (anode). A polarizing voltage is applied to these electrodes that is specific for the reduction of oxygen. A thin, gas permeable membrane isolates the sensor elements from the water sample but allows oxygen to pass through. The oxygen that passes through the membrane is reduced at the cathode, causing a current from which the oxygen concentration is determined. Two-electrode polarographic probes use the anode as a reference electrode.

Portable Meters with Galvanic Probe

The following portable meters use galvanic technology. Galvanic DO probes consist of a working electrode (cathode) and a counter electrode (anode) that act as a battery to produce a voltage specific for the reduction of oxygen. A thin, gas permeable membrane isolates the sensor elements from the water sample but allows oxygen to pass through. The oxygen that passes through the membrane is reduced at the cathode, causing a current from which the oxygen concentration is determined.

OPDO Portable Meters

Portable meters are available that use optical technology to measure dissolved oxygen. Optical DO sensing probe is based on the principle of fluorescence quenching. The sensing method features an immobilized Pt based luminophore that is excited by the light of a blue LED and emits a red light. Dissolved oxygen quenches this excitation. When there is no oxygen present, the lifetime of the signal is the greatest; as oxygen hits the sensing surface, the lifetime becomes shorter. The intensity and lifetime are inversely proportional to the amount of oxygen present; as oxygen interacts with the luminophore it reduces the intensity and lifetime of the luminescence. The lifetime of the luminescence is measured by a photodetector, and is used to calculate the dissolved oxygen concentration. This is in turn reported by the meter as a % saturation or mg/L reading of Dissolved Oxygen.

Portable Meters Portable meters are available with probes that use either the Clarke-Type Polarographic, Galvanic, or Optical technologies. The portable meters include those with manual... read more »
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Portable Meters

Portable meters are available with probes that use either the Clarke-Type Polarographic, Galvanic, or Optical technologies. The portable meters include those with manual calibration and manual selection of altitude and salinity compensation values. Portable meters also include versions that have a barometric pressure transducer for automatic pressure compensation along with versions that have an EC sensor for salinity compensation. Meters are available with the BOD, OUR and SOUR programs built-in for automatic calculation.

Portable Meters with Polarographic Probe

The following portable meters use Clark-Type Polarographic probe. Polarographic DO probes consist of a working electrode (cathode) and a counter electrode (anode). A polarizing voltage is applied to these electrodes that is specific for the reduction of oxygen. A thin, gas permeable membrane isolates the sensor elements from the water sample but allows oxygen to pass through. The oxygen that passes through the membrane is reduced at the cathode, causing a current from which the oxygen concentration is determined. Two-electrode polarographic probes use the anode as a reference electrode.

Portable Meters with Galvanic Probe

The following portable meters use galvanic technology. Galvanic DO probes consist of a working electrode (cathode) and a counter electrode (anode) that act as a battery to produce a voltage specific for the reduction of oxygen. A thin, gas permeable membrane isolates the sensor elements from the water sample but allows oxygen to pass through. The oxygen that passes through the membrane is reduced at the cathode, causing a current from which the oxygen concentration is determined.

OPDO Portable Meters

Portable meters are available that use optical technology to measure dissolved oxygen. Optical DO sensing probe is based on the principle of fluorescence quenching. The sensing method features an immobilized Pt based luminophore that is excited by the light of a blue LED and emits a red light. Dissolved oxygen quenches this excitation. When there is no oxygen present, the lifetime of the signal is the greatest; as oxygen hits the sensing surface, the lifetime becomes shorter. The intensity and lifetime are inversely proportional to the amount of oxygen present; as oxygen interacts with the luminophore it reduces the intensity and lifetime of the luminescence. The lifetime of the luminescence is measured by a photodetector, and is used to calculate the dissolved oxygen concentration. This is in turn reported by the meter as a % saturation or mg/L reading of Dissolved Oxygen.

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