A monitoring device for conducting an analytical measurement of a reaction fluid produced in a reaction vessel in a spectrometer, wherein the monitoring device comprises the following assemblies: a monitoring cell to be arranged in the spectrometer for receiving the reaction fluid to be measured in the spectrometer and transporting it back to the reaction vessel; a distribution device for distributing the reaction fluid between the monitoring cell and the reaction vessel, in which at least two lines (4i', 4o') for the supply of reaction fluid from the reaction vessel to the distribution device and for the return thereof from the distribution device to the reaction vessel and at least two further lines (4i", 4o") for the supply (4i") of reaction fluid from the distribution device to the monitoring cell and for the return (4o") thereof from the monitoring cell open into the distribution device, wherein the distribution device comprises a distribution device for distributing reaction fluid to the at least four supply and return lines (4i', 4o', 4i", 4o'') opening into the distribution device, characterized in that the distribution device comprises a distribution vessel in which the distribution device and an electrically controllable pump device (61; 62a, 62b) for pumping of the reaction fluid are arranged, that the distribution device comprises an electrically controllable valve device for distributing the reaction fluid to the at least four supply and return lines (4i', 4o', 4i", 4o") opening into the distribution vessel, that a control and regulating device is present for electrical control of the pump device (61; 62a, 62b) and for electrical control of the valve device, and that the electrically controllable valve device for distributing the reaction fluid comprises a switchable four-way valve, which, in a first operating position ("on flow"), can connect the supply line from the reaction vessel to the distribution vessel -directly or indirectly - with the supply line (4i") from the distribution vessel to the monitoring cell and the return line (4o") from the monitoring cell to the distribution vessel - directly or indirectly - with the return line from the distribution vessel to the reaction vessel, and which, in a second operating position ("stopped flow"), can connect the supply line from the reaction vessel to the distribution vessel - directly or indirectly - with the return line from the distribution vessel to the reaction vessel and the supply line (4i") from the distribution vessel to the monitoring cell - directly or indirectly - with the return line (4o") from the monitoring cell to the distribution vessel. a monitoring cell to be arranged in the spectrometer for receiving the reaction fluid to be measured in the spectrometer and transporting it back to the reaction vessel; a distribution device for distributing the reaction fluid between the monitoring cell and the reaction vessel, in which at least two lines (4i', 4o') for the supply of reaction fluid from the reaction vessel to the distribution device and for the return thereof from the distribution device to the reaction vessel and at least two further lines (4i", 4o") for the supply (4i") of reaction fluid from the distribution device to the monitoring cell and for the return (4o") thereof from the monitoring cell open into the distribution device, wherein the distribution device comprises a distribution device for distributing reaction fluid to the at least four supply and return lines (4i', 4o', 4i", 4o'') opening into the distribution device, characterized in that the distribution device comprises a distribution vessel in which the distribution device and an electrically controllable pump device (61; 62a, 62b) for pumping of the reaction fluid are arranged, that the distribution device comprises an electrically controllable valve device for distributing the reaction fluid to the at least four supply and return lines (4i', 4o', 4i", 4o") opening into the distribution vessel, that a control and regulating device is present for electrical control of the pump device (61; 62a, 62b) and for electrical control of the valve device, and that the electrically controllable valve device for distributing the reaction fluid comprises a switchable four-way valve, which, in a first operating position ("on flow"), can connect the supply line from the reaction vessel to the distribution vessel -directly or indirectly - with the supply line (4i") from the distribution vessel to the monitoring cell and the return line (4o") from the monitoring cell to the distribution vessel - directly or indirectly - with the return line from the distribution vessel to the reaction vessel, and which, in a second operating position ("stopped flow"), can connect the supply line from the reaction vessel to the distribution vessel - directly or indirectly - with the return line from the distribution vessel to the reaction vessel and the supply line (4i") from the distribution vessel to the monitoring cell - directly or indirectly - with the return line (4o") from the monitoring cell to the distribution vessel.