A device for measuring the total organic carbon content of a sample fluid, comprising: a casing that accommodates: a measuring cell defining a volume for receiving the sample fluid; an excimer lamp arranged to emit radiation having a main wavelength that is suitable to cause an oxidation reaction of organic carbon compounds in the sample fluid contained within the volume of the measuring cell; a pair of electrodes arranged to measure the conductivity of the sample fluid in the volume of the measuring cell; and a first temperature sensor located on the measuring cell, characterized in that the device further comprises at least one second temperature sensor, and the at least one second temperature sensor is arranged to measure a temperature at a location other than at the measuring cell, wherein the at least one second temperature sensor is arranged to measure a temperature related to the sample fluid, preferably before the radiation induced oxidation reaction is started and/or at a location upstream of the volume of the measuring cell, and wherein the device further comprises a control device configured to determine, based on the conductivity and the temperature related to the sample fluid, that the oxidation reaction of organic carbon compounds in the sample fluid has stabilized, and configured to switch off the excimer lamp in accordance with the result of determination. a casing that accommodates: a measuring cell defining a volume for receiving the sample fluid; an excimer lamp arranged to emit radiation having a main wavelength that is suitable to cause an oxidation reaction of organic carbon compounds in the sample fluid contained within the volume of the measuring cell; a pair of electrodes arranged to measure the conductivity of the sample fluid in the volume of the measuring cell; and a first temperature sensor located on the measuring cell, characterized in that the device further comprises at least one second temperature sensor, and the at least one second temperature sensor is arranged to measure a temperature at a location other than at the measuring cell, wherein the at least one second temperature sensor is arranged to measure a temperature related to the sample fluid, preferably before the radiation induced oxidation reaction is started and/or at a location upstream of the volume of the measuring cell, and wherein the device further comprises a control device configured to determine, based on the conductivity and the temperature related to the sample fluid, that the oxidation reaction of organic carbon compounds in the sample fluid has stabilized, and configured to switch off the excimer lamp in accordance with the result of determination. a measuring cell defining a volume for receiving the sample fluid; an excimer lamp arranged to emit radiation having a main wavelength that is suitable to cause an oxidation reaction of organic carbon compounds in the sample fluid contained within the volume of the measuring cell; a pair of electrodes arranged to measure the conductivity of the sample fluid in the volume of the measuring cell; and a first temperature sensor located on the measuring cell, characterized in that the device further comprises at least one second temperature sensor, and the at least one second temperature sensor is arranged to measure a temperature at a location other than at the measuring cell, wherein the at least one second temperature sensor is arranged to measure a temperature related to the sample fluid, preferably before the radiation induced oxidation reaction is started and/or at a location upstream of the volume of the measuring cell, and wherein the device further comprises a control device configured to determine, based on the conductivity and the temperature related to the sample fluid, that the oxidation reaction of organic carbon compounds in the sample fluid has stabilized, and configured to switch off the excimer lamp in accordance with the result of determination.