Rapid analysis of analyte solutions

• US 5,985,120 A
• Filed: 06/12/1997
• Issued: 11/16/1999
• Est. Priority Date: 06/12/1997
• Status: Expired due to Fees

• Current Assignee: University Of Massachusetts
• Original Assignee: University Of Massachusetts
• Inventors: Cholli, Ashok L., Barry, Eugene F., Kumar, Jayant, Tripathy, Sukant K.
• Primary Examiner(s): Till, Terrence R.
• Assistant Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US08/873,473
• Time in Patent Office: 887 Days
• Field of Search: 210/656, 95/25, 95/82, 364/550, 204/451, 204/452, 204/456, 204/461, 204/601, 204/603, 204/606, 204/612, 702/23, 702/24, 702/25, 702/32
• US Class Current: 204/452
• CPC Class Codes: G01N 27/44717 Arrangements for investigating the separated zones, e.g. localising zones
• CPC Class Codes: G01N 27/44721 by optical means

Abstract

The separation profile results of capillary zone electrophoresis can be analyzed very rapidly, e.g., in 45 seconds or less, if the results are analyzed using a successive subtracting procedure to establish the separation profile as a function of time and projecting this separation profile forward in time to quantitatively analyze the separate species in the profile. The projection step can be accomplished using an algorithm along with or without Fourier transform (FT) techniques and the quantitative analysis can be carried out using principle component regression analysis (PCA) or suitable calibration procedures.

Claims

1. A method of measuring concentrations of individual species in a sample, the method comprising:

introducing a sample containing a plurality of individual species into a capillary associated with a detector arranged to detect each of the individual species in the capillary along an analysis length of the capillary;

moving the sample through the capillary for an analysis time to begin separating the individual species in the sample;

measuring a series of profiles of the plurality of individual species along the analysis length of the capillary at incremental sampling times with the detector during the analysis time to provide a data set;

subtracting each profile from the profile measured one sampling time earlier in the data set to obtain a time dependent data set;

projecting the time dependent data set to obtain a separated concentration profile; and

analyzing the separated concentration profile to determine concentrations of individual species in the sample.

2. The method of claim 1, wherein the detector is an absorbance measuring detection device or an array that detects species along the analysis length of the capillary.

3. The method of claim 1, wherein the detector moves along the analysis length of the capillary.

4. The method of claim 3, wherein moving the sample through the capillary comprises applying a voltage across a length of the capillary.

5. The method of claim 4, wherein the applied voltage is varied.

6. The method of claim 1, further comprising applying a time reference shift to each profile in the data set prior to the subtracting step.

7. The method of claim 1, wherein projecting the time dependent data set comprises applying a Fourier transform to the time dependent data set.

8. The method of claim 1, wherein analyzing the separated concentration profile comprises using principle component regression.

9. A method of measuring concentrations of individual species in a sample, the method comprising:

introducing a sample containing a plurality of individual species into a capillary column associated with a detector arranged to detect each of the individual species in the capillary along an analysis length of the capillary;

moving the sample through the column for an analysis time to separate the individual species in the sample;

measuring a series of profiles of the plurality of individual species along the analysis length of the capillary at incremental sampling times with a detector during the analysis time to provide a data set;

applying a Fourier transform to the data set to obtain a separated concentration profile; and

analyzing the separated concentration profile by using principle component regression to determine concentrations of individual species in the sample.

10. The method of claim 9, further comprising subtracting each profile from the profile measured one sampling time earlier in the data set to obtain a time dependent data set.

11. A method of claim 9, wherein the detector is an absorbance measuring detection device or an array that detects species along the analysis length of the capillary.

12. The method of claim 9, wherein the detector moves along the analysis length of the capillary.

13. The method of claim 12, wherein moving the sample through the capillary comprises applying a voltage across a length of the capillary.

14. The method of claim 13, wherein the applied voltage is varied.

15. The system of claim 12, wherein the applied voltage is variable.

20. The system of claim 11, further comprising a power supply arranged to apply a voltage along the length of the capillary for between 1 and 45 seconds.

16. A sensor for measuring species concentrations in a liquid sample, the sensor comprising:

two reservoirs for containing buffer solution;

a capillary connecting the reservoirs, the capillary having an inner diameter of between 25 and 100 micrometers and an effective length of less than 20 cm;

a detector positioned adjacent to the capillary at a distance from the end of the capillary at one of the reservoirs;

a power supply arranged to apply a voltage along the length of the capillary for between 1 and 45 seconds; and

a processor connected to the detector,

wherein the processor identifies individual species in the liquid sample by difference and projection, principle component regression, or Fourier transform analysis.

17. The sensor of claim 16, wherein the absorbance detector detects species along the effective length of the capillary.

18. The sensor of claim 16, wherein the detector position is variable.

19. The sensor of claim 16, wherein the applied voltage is variable.

21. A system for measuring species concentrations in a liquid sample, the sensor comprising:

two reservoirs for containing buffer solution;

a capillary connecting the reservoirs, the capillary having an inner diameter of between 25 and 100 micrometers and an effective length of less than 20 cm;

a detector positioned adjacent to the capillary at a distance from the end of the capillary at one of the resevoirs;

a power supply arranged to apply a voltage along the length of the capillary for between 1 and 45 seconds; and

a processor connected to the detector,

wherein the processor identifies individual species in the liquid sample by difference and projection, principle component regression, or Fourier transform analysis.

22. The sensor of claim 21, wherein the absorbance detector detects species along the effective length of the capillary.

23. The sensor of claim 21, wherein the detector position is variable.

24. The sensor of claim 21, wherein the applied voltage is variable.

25. The sensor of claim 21, wherein the liquid sample is substantially aqueous.