Spectroscopy of urine

[Lykkeland]

I'm an electrical engineer, and right now i am working with a system that is supposed to detect the amount of different substances in urine. Including glucose, urea, creatinine, ketons, proteins, leukocytes, nitrite, urobilinogen, hemoglobin and bilirubin.

The way we want do detect the substances is in an external way, no direct contact with the urine. So we're going to use spectroscopy, sending different wavelength through the sample. Then analyze the the wavelengths to figure out the amount.

So what i'm thinking about now is to order solutions of the different substances, and i have decided to try out urea and creatinine first (the amount og these substances is high in urine). But what should i think about when ordering these solutions in order to make the wavelength spectrum look like the spectrum of real urine? Should the solutions consist of only creatinine and water, or do i need any salts with it?
If you have any other tips or important thing i should focus/think about in this project, then yell out.

Im sorry for my english and my limited knowledge of chemistry.
Best regards Simon.

[Lykkeland]

Does anybody have any knowledge about this?