The Perkin-elmer Corporation

Edward B Delany

Charles C Helms

Arnold Schwartz

Ralph D Conlon

A beam of radiation is directed into a liquid sample cell containing a sample to be analyzed in solution. The illumination emanating from the sample cell as a result of the beam of radiation from the radiation source is diffracted into a polychromatic spacially divergent beam and directed to a linear array of photovoltaic photodetectors with different spectral segments of the beam being intercepted by different photodetectors of the array. The signals from the photodetectors are separately and substantially simultaneously sampled and held to thereby obtain data usable for a high-accuracy wide-spectrum chromatogram.

Instantaneous reading multichannel polychromatic spectrophotometer

In a solvent gradient liquid chromatography system, base line shift is compensated by operating the system in a calibrate cycle with a desired solvent gradient program while subtracting and recording in digital form correction factors sufficient to maintain a flat base line at timed intervals during the program, and then successively recalling said digital correction factors at corresponding time intervals during a run cycle with a test sample and converting the correction factors to analog form and subtracting the converted correction factors from the system output signal for base line correction.

Base line correction method and apparatus

Thermocouples are disposed in the flame exhaust passage and exteriorly on the housing of each ionization detector to monitor the flame status thereof within an environment of widely varying temperature. A temperature differential signal is derived from the thermocouples of each ionization detector, with each temperature differential signal being compared to a common threshold level at which an indication of a flameout condition occurs. The indication of a flameout condition in each ionization detector is varied relative to the temperature differential thereof through a variable gain amplification stage. Switches are disposed for individually interrupting each temperature differential signal and flameout conditions occurring in any one or more of the ionization detectors are identifiable therewith.

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Ridgefield, CT, United States of America

Edward B Delany