A SPECTROMETER APPARATUS FOR MEASURING SPECTRA OF A LIQUID SAMPLE USING AN INTEGRATING CAVITY

A spectrometer apparatus (1) is provided for measuring spectra of a liquid sample, such as a beverage such as wine. The apparatus (1) comprises an integrating cavity (3) comprising a reflective inner wall or walls (5), configured to receive a cuvette (7) containing the liquid sample within the integrating cavity (5). A combination of light inlet ports P1, P2 and light outlet ports P3, P4 are provided to receive light from at least one light source (9) and to deliver light to a spectrometer (11). A light path adjuster (13, 13B) is configured to selectively adjust a light path through the integrating cavity (5) such that at least two distinct light paths are provided; wherein when the light path adjuster (13, 13B) is in a first configuration, the apparatus (1) is in a transmission mode in which light from the light source follows a first light path (15) from the or one of the light inlet port(s) to the liquid sample such that the light from the light source irradiates the liquid sample directly before the light transmitted by the sample is transmitted through the or one of the light outlet port(s) and received by the spectrometer (11) for wavelength analysis of the light to provide an extinction spectrum of the liquid sample; and when the light path adjuster (13, 13B) is in a second configuration, the apparatus is in a diffusely reflecting mode in which light from the light source follows a second light path (17) from the or one of the inlet port(s) into the integrating cavity, is incident onto the reflective inner wall or walls of the integrating cavity and is diffusely reflected within the integrating cavity, such that the light from the light source irradiates the liquid sample before being transmitted through the or one of the light outlet port(s) and received by the spectrometer (11) for wavelength analysis of the light to provide an absorbance spectrum of the liquid sample contained in the liquid sample.