Oxygraph Plus Electrode Control Unit

The next generation Oxygraph Plus oxygen electrode control unit combines striking aesthetics with enhanced features and functionality offering significant advances in functionality and performance over previous generations of electrode control units.

In conjunction with user-friendly O2view data acquisition and system configuration software, the Oxygraph Plus electrode control unit provides an effective tool for the measurement of oxygen signals from the S1 Clark type electrode disc mounted in one of a range of liquid and gas-phase oxygen electrode chambers with quick and easy system calibration and configuration. In addition, Oxygraph Plus is equipped with integral systems to allow the calibration and simultaneous measurement of either a pH or other ion-selective electrode (ISE) signal e.g. Ca+, TPP+ or an auxiliary input signal.

The Oxygraph Plus electrode control unit communicates with the PC via USB2.0 representing a significant advantage over the older RS232 serial communications and the well-known associated difficulties of using RS232 – USB adapters. Oxygraph Plus control units may be configured as single or multi-channel systems of up to 8 units allowing comparative measurements of multiple samples to be made conveniently and effectively. Multiple control units connect to a powered USB2.0 hub which is in turn connected to an available USB2.0 port of a Windows® PC.

Oxygraph Plus is designed with state-of-the-art electronics providing 24 bit high resolution for oxygen measurements with 16 bit resolution for ISE and auxiliary input signals. This significant development removes the requirement for gain and back-off associated with previous generations of control unit and also renders overscale problems obsolete. A 0 – 4.5V analogue output is fitted to the rear of the control unit allowing real-time output of the oxygen electrode signal to external recording/logging devices.

As with legacy oxygen electrode control units, Oxygraph Plus features an integral magnetic stirrer and all the electronics required to control and measure the signal from connected electrodes and is compatible with all existing liquid and gas-phase Hansatech oxygen electrode chambers and accessories.

 

DW1/AD

The DW1/AD oxygen electrode chamber provides a highly versatile solution to measurements of dissolved oxygen in liquid-phase samples. It can be used for a wide range of applications from basic teaching through to more advanced research assays.

Due to the gas-tight plunger assembly, the DW1/AD lends itself particularly well to respiration assays in small sample volumes where any minute diffusion of ambient oxygen into the chamber may cause measurement artefacts.

The DW1/AD oxygen electrode chamber is constructed from clear cast acrylic providing good sample visibility & uniform illumination. Precise temperature control of the sample and electrode disc can be achieved by connecting the water jacket of the DW1/AD to a thermoregulated circulating water bath.

The sample is housed within a borosilicate glass reaction vessel which has a variable sample volume of between 0.2 and 2.5ml controlled by the gas-tight adjustable plunger assembly. This plunger has a stoppered central precision bore allowing additions/subtractions to be made to/from the reaction mixture using a standard Hamilton type syringe.

 

S1 Electrode Disk

The S1 electrode was designed in the early 1970’s during a collaborative project between Prof. David Walker, Prof. Tom Delieu and Hansatech Instruments. Since the first S1 oxygen electrode disc went on sale in 1974, the design and manufacturing process has remained largely unchanged in nearly 40 years – a true testament to the popularity, quality and reliability of the sensor.

A range of complementary instruments have been continuously developed over the years in order to meet the needs of emerging trends in the scientific world. Modern oxygen measurement systems incorporate the S1 electrode to provide sensitive and reliable tools for a vast range of applications from the demonstration of oxygen evolution from photosynthetic organisms to the analysis of mitochondrial respiration rates.

When prepared and fitted into an electrode chamber, the dome of the electrode disc forms the floor of the electrode chamber reaction vessel providing a sensitive and rapid response to small changes in oxygen tension within the sample.

The electrode disc comprises a central platinum cathode and a concentric silver anode. Preparation of the electrode includes the addition of electrolyte and the application of a thin oxygen permeable P.T.F.E. membrane to the electrode dome.

Once prepared and positioned in the electrode chamber, the disc is connected to an electrode control unit which applies a small polarising voltage between the platinum and silver electrodes. In the presence of oxygen, a small current is generated proportional to oxygen activity in the sample.

With modifications and in conjunction with accessory equipment, the S1 oxygen electrode disc may be used to measure other gasses such as hydrogen and nitric oxide.