Methods and apparatus for analyzing samples and collecting sample fractions

1. A method of detecting and collecting one or more sample components within a first sample stream in a chromatography system during a chromatographic run comprising:

passing the first sample stream through a chromatography column;

actively splitting a portion of the first sample stream exiting the column to form a second sample stream that is in fluid communication with an evaporative particle detector, the first sample stream being in fluid communication with an optical absorbance detector,

where the first sample stream does not pass through the evaporative particle detector and the second sample stream does not pass through the optical absorbance detector, and where the optical absorbance detector monitors an absorbance spectrum or a range of wavelengths within a spectrum and generates response values from each of the monitored wavelengths;

generating a first signal resulting from the response values associated with each of the wavelengths monitored by the optical absorbance detector during the chromatographic run;

generating a second signal resulting from a response from the evaporative particle detector during the chromatographic run; and

collecting at least one component from the first stream in a fraction collector during the chromatographic run in response to information generated during the chromatographic run, said information consisting of a change in at least one of said signals;

wherein the splitting step is performed with use of a splitter pump or a shuttle valve.

2. The method of claim 1 wherein said splitter pump is positioned in said second stream upstream of said evaporative particle detector.

3. The method of claim 1 or 2 in which said information includes at least a change in said first signal.

4. The method of claim 1 or 2 in which said information includes at least a change in said second signal.

5. The method of claim 1 or 2 in which said information includes a change in both signals.

6. The method of claim 1 or 2 in which at least said first signal is based on the first derivative or the second derivative of response values of its respective detector.

7. The method of claim 1 or 2 in which at least said second signal is based on the first derivative or the second derivative of the response values of its respective detector.

8. The method of claim 1 or 2 in which both signals are based on the first derivative or the second derivative of the response values of their respective detectors.

9. A chromatographic apparatus for detecting and collecting one or more sample components within a first sample stream in a chromatography system during a chromatographic run comprising:

a chromatography column in fluid communication with said first sample stream;

means for actively splitting a portion of the first sample stream exiting the column to form a second sample stream;

an optical absorbance detector in fluid communication with the first sample stream that is capable of monitoring an absorbance spectrum or a range of wavelengths within a spectrum and generating response values from each of the monitored wavelengths;

an evaporative particle detector in fluid communication with the second sample stream that is capable of generating at least one response value;

where the splitting means and the detectors are arranged such that the first sample stream does not pass through the evaporative particle detector and the second sample stream does not pass through the optical absorbance detector;

a processor; and

a fraction collector to collect components from the first stream during the chromatographic run, where the processor is adapted to receive said response values from said detectors generated during the chromatographic run and to generate output during said chromatographic run to which the fraction collector is responsive, said output including information to which the fraction collector is responsive, said information consisting of a change in one or more response values from the optical absorbance detector or a change in a response value from the evaporative particle detector, or both;

wherein said means comprises a splitter pump or shuttle valve.

10. The apparatus of claim 9 wherein said splitter pump is positioned in said second stream upstream of said evaporative particle detector.

11. The apparatus of claim 9 or 10 in which said information includes at least a change in one or more response values from the optical absorbance detector.

12. The apparatus of claim 11 in which said output is based on the first derivative or the second derivative of said response values.

13. The apparatus of claim 9 or 10 in which said information includes at least a change in a response value from the evaporative particle detector.

14. The apparatus of claim 13 in which said output is based on the first derivative or the second derivative of said response values.

15. The apparatus of claim 9 or 10 in which said output is based on the first derivative or the second derivative of the response values from both detectors.