Sample analyser for analysing a sample solution, in particular contaminated water or waste water, with a reaction vessel for the thermal digestion of a measured sample of the sample solution to be analysed, the reaction vessel having an injection port for introducing the sample into the reaction vessel, at least one sample solution storage vessel for storing sample solution within the apparatus, and an injection syringe device movable between the sample solution storage vessel and the reaction vessel and controllable for picking up the sample from the sample solution storage vessel and for introducing the sample into the injection port of the reaction vessel, characterised in that at least a first and a second sample solution storage vessel are provided, wherein the second sample solution storage vessel is designed for the preparation and storage of diluted sample solution, and the injection syringe device is designed for introducing sample solution taken up from the first sample solution storage vessel optionally into the second sample solution storage vessel for producing the diluted sample solution, wherein the second sample solution storage vessel is connected to a controllable water connection for supplying distilled water for diluting sample solution, and has an inner vessel for producing and storing the diluted sample solution, on the wall of which an overflow region is provided at least in sections for draining off excess diluted sample solution, and wherein the first and second sample solution storage vessels each have an upper end face which is closed by a septum which can be pierced by an injection needle of the hypodermic syringe device. a reaction vessel for the thermal digestion of a measured sample of the sample solution to be analysed, the reaction vessel having an injection port for introducing the sample into the reaction vessel, at least one sample solution storage vessel for storing sample solution within the apparatus, and an injection syringe device movable between the sample solution storage vessel and the reaction vessel and controllable for picking up the sample from the sample solution storage vessel and for introducing the sample into the injection port of the reaction vessel, characterised in that at least a first and a second sample solution storage vessel are provided, wherein the second sample solution storage vessel is designed for the preparation and storage of diluted sample solution, and the injection syringe device is designed for introducing sample solution taken up from the first sample solution storage vessel optionally into the second sample solution storage vessel for producing the diluted sample solution, wherein the second sample solution storage vessel is connected to a controllable water connection for supplying distilled water for diluting sample solution, and has an inner vessel for producing and storing the diluted sample solution, on the wall of which an overflow region is provided at least in sections for draining off excess diluted sample solution, and wherein the first and second sample solution storage vessels each have an upper end face which is closed by a septum which can be pierced by an injection needle of the hypodermic syringe device.