Abstract: Sample injection system for nonsegmented, continuous flow analysis comprising an inlet channel, an analyzer channel and a carrier stream channel connected in a confluence point, an aspirating pump in the analyzer channel, a carrier stream pump in the carrier stream channel with a higher capacity than the aspirating pump and an analyzer. In a first step prior to the sample injection, the carrier stream pump forwards carrier stream to the confluence point, the aspirating pump sucks carrier stream from the confluence point, at a lower rate than the carrier stream pump and an outflow of carrier stream drains through the inlet channel. In a second step, the carrier pump is stopped, the inlet end of the inlet channel is brought in contact with the sample solution, and the aspirating pump sucks sample into the inlet channel and the analyzer channel.