An ATR infrared spectrometer for analyzing a chemical composition of a sample is provided including an elongated ATR crystal and having an entrance face, a longitudinal axis, a width, first and second longitudinal ends and an infrared light detector line with infrared-light-detecting regions. A first overall extent of all of the infrared-light-detecting regions corresponds to the width of ATR crystal. An infrared light emitter line has infrared-light-emitting regions and is arranged directly adjacent to the entrance face of the elongated ATR crystal. A sample is arranged adjacent to the ATR crystal between the infrared light emitter line and the infrared light detector line. Infrared light is emitted by the infrared light emitter line to directly enter said ATR crystal via said entrance face. The light is guided in the ATR crystal to said infrared light detector line thereby undergoing total internal reflection and thereby interacting with said sample.