qPCR using solid-state sensing

A method of detecting a target nucleic acid by monitoring nucleic acid amplification in a sample comprising a buffered nucleic acid amplification mixture for amplification of a sequence of the target nucleic acid if present in the sample, characterised in that said monitoring comprises detecting a change of pH resulting from proton release in the presence of the target sequence as amplification proceeds beyond a threshold number of cycles to produce multiple copies of the target sequence such that buffering capacity of the sample is overcome, said detecting employing a sensing apparatus comprising an ISFET having a sensing surface exposed to the sample and arranged to generate an electrical output signal in response to the change of pH at said transistor surface and a detector for the electrical output signal from the ISFET, and wherein detection of the change of pH once the buffering capacity is overcome correlates with detection of the target nucleic acid.