of a solute in a solvent disclosed is an apparatus or method for determining the concentration of a solute in a solvent of a solution in a container having a time varying volume by analyzing two signals received from the solution comprising measuring the quantity of the two received signals converting the two signals into two electro optical or electrical signals performing a mathematical transformation on the two electro optical or electrical signals and determining the ratio of the transformation components of the two electro optical or electrical signals the present invention can be used in various applications of determining the ingredient concentration of a fluid such as a gas or liquid particularly the present invention finds applications in blood analysis in a human body for measuring for example the glucose triglycerol cholesterol or oxyhemoglobin concentrations of the blood application_number US 75243704 A description the present invention is based on an important recognition that the induced signal from a solvent is mixed with the same noise as the induced signal from the ingredient is taking the blood for example the induced signal from water is mixed with the noise that is the same as the noise mixing with the induced signal from glucose the same noise is.