A voltammetric analysis system for conducting voltammetric analysis of an analyte, the system comprising: a mobile computing device; a voltammetric cell for receiving the analyte, and comprising first and second electrodes (104, 106); and a circuit configuration comprising a resistor and a capacitor for connecting the mobile computing device to the voltammetric cell, wherein the mobile computing device comprises: a microprocessor; one or more memory components comprising a program and data store accessible to the microprocessor; and an audio interface comprising an audio signal output having first and second channels and an audio signal input, which is operable under control of the microprocessor, characterised in that wherein the audio interface is connected, in use, to the voltammetric cell with the first channel of the audio signal output being connected to the first electrode, the second channel of the audio signal output being connected to the second electrode via the resistor, and the audio signal input being connected to the second electrode via the capacitor; and the program and data store containing instructions which, when executed by the microprocessor, cause the mobile computing device to function as a potentiostat by implementing steps of: generating an output voltage waveform (310, 312) between the first and second channels of the audio signal output, the output voltage waveform comprising a time-varying voltammetric driving potential and an AC perturbation; simultaneously with generating the output voltage waveform, capturing an input voltage waveform received at the audio signal input; and recording within the data store the input voltage waveform as a voltammetric response waveform. a mobile computing device; a voltammetric cell for receiving the analyte, and comprising first and second electrodes (104, 106); and a circuit configuration comprising a resistor and a capacitor for connecting the mobile computing device to the voltammetric cell, wherein the mobile computing device comprises: a microprocessor; one or more memory components comprising a program and data store accessible to the microprocessor; and an audio interface comprising an audio signal output having first and second channels and an audio signal input, which is operable under control of the microprocessor, characterised in that wherein the audio interface is connected, in use, to the voltammetric cell with the first channel of the audio signal output being connected to the first electrode, the second channel of the audio signal output being connected to the second electrode via the resistor, and the audio signal input being connected to the second electrode via the capacitor; and the program and data store containing instructions which, when executed by the microprocessor, cause the mobile computing device to function as a potentiostat by implementing steps of: generating an output voltage waveform (310, 312) between the first and second channels of the audio signal output, the output voltage waveform comprising a time-varying voltammetric driving potential and an AC perturbation; simultaneously with generating the output voltage waveform, capturing an input voltage waveform received at the audio signal input; and recording within the data store the input voltage waveform as a voltammetric response waveform. a microprocessor; one or more memory components comprising a program and data store accessible to the microprocessor; and an audio interface comprising an audio signal output having first and second channels and an audio signal input, which is operable under control of the microprocessor, characterised in that wherein the audio interface is connected, in use, to the voltammetric cell with the first channel of the audio signal output being connected to the first electrode, the second channel of the audio signal output being connected to the second electrode via the resistor, and the audio signal input being connected to the second electrode via the capacitor; and the program and data store containing instructions which, when executed by the microprocessor, cause the mobile computing device to function as a potentiostat by implementing steps of: generating an output voltage waveform (310, 312) between the first and second channels of the audio signal output, the output voltage waveform comprising a time-varying voltammetric driving potential and an AC perturbation; simultaneously with generating the output voltage waveform, capturing an input voltage waveform received at the audio signal input; and recording within the data store the input voltage waveform as a voltammetric response waveform. generating an output voltage waveform (310, 312) between the first and second channels of the audio signal output, the output voltage waveform comprising a time-varying voltammetric driving potential and an AC perturbation; simultaneously with generating the output voltage waveform, capturing an input voltage waveform received at the audio signal input; and recording within the data store the input voltage waveform as a voltammetric response waveform.