Reagentless analysis of biological samples by applying mathematical algorithms to smoothed spectra

A method for determination of concentration of at least one analyte of interest in a biological sample by means of spectroscopic analysis, said method comprising the steps of:

• (a) providing the biological sample in the form of a liquid, said liquid comprising water and at least one analyte dissolved in the water, wherein the water has a spectrum and the at least one analyte has a spectrum different from that of water;
• (b) identifying a mathematical function that is substantially similar to a region of a non-smoothed spectrum of said sample over a selected range of the non-smoothed spectrum;
• (c) determining a portion of said region of said non-smoothed spectrum having noise that is substantially random;
• (d) determining coefficients of said mathematical function that result in a close fit of the function to said selected portion of said non-smoothed spectrum;
• (e) calculating at least one of a parameter value of said non-smoothed spectrum at at least one wavelength of said non-smoothed spectrum by means of said coefficients of step (d), wherein said at least one wavelength includes the center of said region of said non-smoothed spectrum;
• (f) assigning said at least one calculated value of said non-smoothed spectrum to a wavelength including the center of said selected portion of said region of said non-smoothed spectrum to form at least one point of a smoothed spectrum;
• (g) shifting a selected distance in said non-smoothed spectrum and repeating steps (d), (e) and (f) until said smoothed spectrum is formed;
• (h) forming a residual spectrum by subtracting each point of said smoothed spectrum at a given wavelength from each point of said non-smoothed spectrum at said given wavelength;
• (i) inspecting said residual spectrum to determine if it is random, and if said residual spectrum is not random, repeating steps (c), (d), (e), (f), (g), and (h) to achieve a desired smoothed spectrum;
• and
• (j) after achieving the desired smoothed spectrum, determining the analyte concentration from the desired smoothed spectrum.