Method for determining analyte concentration using periodic temperature modulation and phase detection

A method of spectroscopically analyzing a test sample utilizing a radiation detector and a means for inducing a thermal gradient in said sample, said method comprising the steps of:

• a) providing a test sample;
• b) inducing a thermal gradient in said test sample;
• c) responsive to said inducing step, measuring at least one reference signal emitted by said sample;
• d) further responsive to said inducing step, measuring at least one analytical signal emitted by said sample;
• e) comparing said measured reference and said analytical signals to determine phase difference information between said analytical and reference signals;
• f) using the magnitude of said phase difference to determine sample analyte concentration information;
• and
• g) transmitting said concentration information, as an electrical signal for further processing.

A method of determining the absolute or relative concentration of a chemical analyte in a medium, said method comprising the steps of:

• a) inducing at least one periodically modulated thermal gradient into said medium;
• b) responsive to said inducing step, measuring the radiation emitted from said medium at a predetermined wavelength related to said analyte, resulting in an analytical signal;
• c) further responsive to said inducing step, measuring the radiation emitted from said medium at least one reference wavelength, resulting in at least one reference signal;
• d) comparing the analytical signal with at least one of said at least one reference signal;
• e) determining from said comparison, the phase difference between said analytical signal and said at least one reference signal to produce at least one phase signal;
• and
• f) deducing from said at least one phase signal the concentration of said analytes in said medium.

A method of determining the absolute or relative concentration of a chemical analyte in a medium, said method comprising the steps of:

• a) inducing a shallow temperature gradient in said medium using a first driving frequency;
• b) inducing a deep temperature gradient in said medium using a second driving frequency;
• c) responsive to said step of inducing a shallow temperature gradient, measuring a shallow analytical signal and at least one shallow reference signal;
• d) responsive to said step of inducing a deep temperature gradient, measuring a deep analytical signal and at least one deep reference signal;
• e) comparing the shallow analytical signal with said at least one shallow reference signal;
• f) comparing the deep analytical signal with said at least one deep reference signal;
• g) determining from the comparison of said shallow signals, a parameter difference between said shallow analytical signal and said at least one shallow reference signal to produce at least one shallow parameter difference signal;
• h) determining from the comparison of said deep signals, the parameter difference between said deep analytical signal and said at least one deep reference signal to produce at least one deep parameter difference signal;
• i) analyzing said at least one shallow parameter difference signal together with said at least one deep parameter difference signal to determine a combined parameter difference signal;
• and
• j) deducing from said combined parameter difference signal, the concentration of said analytes in said medium.

A method of determining the absolute or relative concentration of blood glucose in a human or animal subject, said method comprising the steps of:

• a) providing a human or animal test subject;
• b) inducing two periodic thermal gradients in the skin of said test subject, a first gradient being driven at a first frequency and a second gradient being driven at a second frequency, said second gradient driving frequency being greater than said first gradient driving frequency, whereby said second frequency providing a second gradient which extends to the shallower regions of the skin and said first frequency providing a first gradient which extends deeper into the skin than said second gradient;
• c) responsive to said inducing of the first gradient, measuring the radiation emitted from the deeper regions of the skin at a glucose absorbance peak wavelength, resulting in a first analytical signal and at one or more one reference wavelengths, resulting in a first reference signal;
• d) responsive to said inducing of the second gradient, measuring the radiation emitted from the shallower regions of the skin at a glucose absorbance peak wavelength, resulting in a second analytical signal and at one or more one reference wavelengths, resulting in a second reference signal;
• e) comparing the first analytical signal with said one or more first reference signals to determine a the phase differences between said first analytical signal and said first reference signals producing at least one first phase signal;
• f) comparing the second analytical signal with said one or more second reference signals to determine a the phase differences between said second analytical signal and said second reference signals producing at least one second phase signal;
• g) said at least one first phase signal together with said at least one second phase signal to determine a combined phase signal;
• and
• j) deducing from said combined phase signal, the blood glucose concentration in said test subject.
• k) transmitting said blood glucose concentration information, as an electrical signal, for further processing.

A method of determining the absolute or relative concentration of a chemical analyte in a medium, said method comprising the steps of:

• a) inducing at least one thermal gradient into said medium;
• b) responsive to said inducing step, measuring the radiation emitted from said medium at a predetermined wavelength related to said analyte, resulting in an analytical signal;
• c) further responsive to said inducing step, measuring the radiation emitted from said medium at least one reference wavelength, resulting in at least one reference signal;
• d) comparing the analytical signal with at least one of said at least one reference signals;
• e) determining from said comparison, a parameter between said analytical signal and said at least one reference signal;
• and
• f) deducing from said parameter the concentration of said analytes in said medium.