An apparatus for determination of information regarding the composition of a liquid sample comprising: a radiation source and a radiation detector system (3; 21) spaced therefrom to define a scanning zone therebetween and to collect in use a dataset of information about radiation incident at the detector and hence transmissivity of a liquid sample in the scanning zone, the radiation detector system being capable of generating spectroscopic information about the transmitted radiation; a sample retention means adapted to hold a liquid sample in a static position in the scanning zone; a data processing apparatus (22, 23, 24) to process and resolve such dataset spectroscopically across at least three frequency bands within the spectrum of the source to produce an intensity data item for each frequency band; a mass attenuation data library storing mass attenuation data for a plurality of expected constituent ingredients of the liquid; a comparator to fit each intensity data item to the relationship given by the exponential attenuation law: I / I 0 = exp − μ / ρ ρ t in respect of the constituent ingredients and derive therefrom an indication of relative proportions of the constituent ingredients in a transmission path producing the said intensity data items; wherein the detector system is capable of generating spectroscopic information about the transmitted radiation in that it comprises a detector element fabricated from a semiconductor material selected to exhibit inherently as a direct material property a direct variable photoelectric response to different parts of the spectrum of the radiation spectrum of the source; and wherein the apparatus comprises at least one standard container of known radiation transmission properties and size in which a liquid sample under test may be contained in use and means configured to use the known size of the container in the above equation and to identify the contribution of the container to the result of the relative proportions of the constituent ingredients and to subtract it from the result. a radiation source and a radiation detector system (3; 21) spaced therefrom to define a scanning zone therebetween and to collect in use a dataset of information about radiation incident at the detector and hence transmissivity of a liquid sample in the scanning zone, the radiation detector system being capable of generating spectroscopic information about the transmitted radiation; a sample retention means adapted to hold a liquid sample in a static position in the scanning zone; a data processing apparatus (22, 23, 24) to process and resolve such dataset spectroscopically across at least three frequency bands within the spectrum of the source to produce an intensity data item for each frequency band; a mass attenuation data library storing mass attenuation data for a plurality of expected constituent ingredients of the liquid; a comparator to fit each intensity data item to the relationship given by the exponential attenuation law: I / I 0 = exp − μ / ρ ρ t in respect of the constituent ingredients and derive therefrom an indication of relative proportions of the constituent ingredients in a transmission path producing the said intensity data items; wherein the detector system is capable of generating spectroscopic information about the transmitted radiation in that it comprises a detector element fabricated from a semiconductor material selected to exhibit inherently as a direct material property a direct variable photoelectric response to different parts of the spectrum of the radiation spectrum of the source; and wherein the apparatus comprises at least one standard container of known radiation transmission properties and size in which a liquid sample under test may be contained in use and means configured to use the known size of the container in the above equation and to identify the contribution of the container to the result of the relative proportions of the constituent ingredients and to subtract it from the result.