Analysis of an Acoustically Separated Liquid

An analyser is provided comprising a sample chamber for holding a liquid sample containing particles and an ultrasound source acoustically couplable to the sample chamber to supply resonant ultrasound energy for acoustically concentrating particles in the liquid sample in nodal planes established thereby. A probe is also provided which is adapted to supply electromagnetic energy into the sample chamber and to receive the supplied electromagnetic energy from the sample chamber at least during a time at which particles are substantially concentrated in associated nodal planes. The analyser is provided with an analysis unit in operable connection to a detector of the optical probe and is adapted to determine one or both a quantitative and a qualitative property of the liquid sample from the received electromagnetic energy.