Aber Instruments, Inc.

Other

Robert W Todd

Douglas B Kell

An apparatus is disclosed which uses electrodes to analyse a test sample.

Analysis of a test sample

The invention relates to a probe for measuring the biomass content in a medium having a suspending fluid and cells. The probe has at least three electrodes, wherein two of the electrodes are configured as excitation electrodes for transmitting an excitation signal through a medium. Two of the electrodes are configured as signal electrodes for receiving an excitation signal that has passed through the medium. The or each signal electrode is located between the two excitation electrodes at a position where a high current density is generated. The probe can have two excitation electrodes and four signal electrodes. The signal electrodes are configured substantially in parallel and arranged in couples adjacent each other, at positions between the excitation electrodes. The signal electrodes are configured such that (i) a first couple of signal electrodes are arranged between the closest end points of the excitation electrodes at one side of the probe, and (ii) a second couple of signal electrodes are arranged between the closest end points of the excitation electrodes at the other side of the probe.

Probe for measuring the biomass content in a medium

Method for determining gas hold-up

Apparatus for the determination of biomass in a suspension and its use in a fermentation apparatus. The apparatus includes electrodes to be placed in the suspension and the following other components: circuit for applying an alternating voltage between the electrodes; circuit for providing a current signal indicative of the current in the current electrode circuit; circuit for providing a voltage signal indicative of the voltage between the ratio between the value of the voltage signal and the value of a quadrature component of the current signal, or vice versa, to provide a capacitance dependent signal.

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Aberystwyth, United Kingdom

Robert W Todd