The Oxygraph oxygen electrode control unit is designed to provide PC control of oxygen uptake or evolution measurements across a broad range of applications from studies of mitochondrial and cellular respiration to studies of isolated chloroplast suspensions or leaf-discs in photosynthesis research applications. In conjunction with user-friendly Oxygraph Plus data acquisition and system configuration software, the Oxygraph oxygen 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.

An Oxygraph system may be configured as a single or multi-channel setup in order to make comparative measurements of oxygen in either liquid or gas-phase from multiple samples. Simultaneous recording of an optional auxiliary input signal (e.g. temperature, pH, fluorescence, TPP+ or other specific ion electrodes etc) is also possible using the appropriate apparatus coupled via the OXY/AUX adapter cable.

A system comprises a minimum of one (maximum of eight) Oxygraph control units linked together in a chain to the serial port of a Windows® PC. Each control unit features a built-in magnetic stirrer and all the electronics required to control and measure the signal from the oxygen electrode. Oxygraph is compatible with all existing liquid and gas-phase Hansatech oxygen electrode chambers and accessories. Oxygraph control units may be freely interspersed with Oxytherm electrode control units within a multi-channel system. The control unit connects to a PC via the serial port and uses bi- directional RS232 communications for instrument control from the PC and data acquisition to the PC. There is no requirement for separate loggers, internal PC interfaces or A/D cards. Laptop or notebook computers are therefore just as suitable as a desktop PC and provide a highly portable, compact system whenever bench space is limited.

A custom Windows® software package, Oxygraph Plus, is supplied with the Oxygraph electrode control unit. The software is designed to provide control of all hardware functions from simple dialogue based controls. Oxygraph Plus contains Wizard-type semi-automated calibration routines for liquid or gas-phase measurements allowing system calibration to be performed with ease by following a series of onscreen prompts in order to record the signal from the S1 electrode at 2 known oxygen concentrations. Signal gain and back-off controls are also included in Oxygraph Plus which may be used to amplify smaller signals from samples with lower oxygen concentrations.

Once calibrated, Oxygraph Plus records the signal from the S1 electrode disc (and an optional auxiliary input signal) at a user-defined data acquisition rate and presents the values as a real-time chart recorder emulation. Recorded values are also presented in a digital panel meter in calibrated units along with a Live Rate measurement which is calculated in real-time over a user-defined number of recorded data points.

Once the recording is complete, Oxygraph Plus contains several tools for basic analysis of the recorded data. A rate measurement tool provides easy estimation of oxygen rates over user-defined intervals and spot measurement tool allows precise oxygen and time base values to be obtained for any given point on the recorded trace. Data files are saved in a Comma Separated Values (*.CSV) format which may be opened directly in external data analysis packages, such as Microsoft Excel®, for more detailed statistical and graphical analysis of recorded data.