Valco Instruments Company, Inc.

Other

Huamin Cai

Stanley D Stearns

Chris S Cowles

Chris Bishop

Dale Ashworth

Robert Simpson

Douglas Dailey

Wayne E Wentworth

Matias Hochman

A temperature controller for simultaneously controlling the temperatures of a plurality of heating elements for use in chromatographic analysis including columns, detectors, valves, transport lines and other components.

Chromatographic system temperature control system

A detector for gas chromatography using two or more ionization sources within a single body to separately provide ionization energy to a column gas eluent to provide electrical discharge to two or more collecting electrodes provides improved selectivity and may be so used. Use is made of combined bias/collecting electrodes or of sets of separated bias and collecting electrodes. The use of multiple ionization sources permits generation of multiple detector outputs from within a common body and of a common constituent flow. The ionization sources and any applicable discharge gas and dopant may be selected based on desired selectivity.

Photo ionization detector for gas chromatography having at least two separately ionizing sources

A pulsed discharge helium ionization detector for gas chromatography with multiple combined bias/collecting electrodes.

Pulsed discharge helium ionization detector with multiple combined bias/collecting electrodes for gas chromatography and method of use

A detector for gas chromatography using two ionization sources within a single body to separately provide ionization energy to a column gas eluent to provide electrical discharge to two or more collecting electrodes provides improved selectivity and may be so used. Use is made of combined bias/collecting electrodes. The use of two ionization sources permits generation of two detector outputs from within a common body and of a common constituent flow. The ionization sources and any applicable discharge gas and dopant may be selected based on desired selectivity.

Photo ionization detector for gas chromatography having two separately ionizing sources and methods of use

The adaptive temperature controller system includes a device for measuring resistance, an electrically-conductive material, a power supply, and a device for controlling power. In operation, the controller determines the resistance of material at one or more temperatures and therefore determines the resistance of the material through a range of operating temperature. Based on such determination so long as voltage and power are known, the resistance of the material, and therefore its temperature, are known. As a result the voltage or power may be instantly varied to produce near infinite control over material temperature.

Adaptive temperature controller

The adaptive temperature controller includes a device for measuring resistance, an electrically-conductive material, a power supply, and a device for controlling power. In operation, the controller determines the resistance of material at one or more temperatures and therefore determines the resistance of the material through a range of operating temperature. Based on such determination so long as voltage and power are known, the resistance of the material, and therefore its temperature, are known. As a result the voltage or power may be instantly varied to produce near infinite control over material temperature.

This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Method of modulating a second carrier for partial modulation via pulsed flow modulator for comprehensive two-dimensional liquid or gas chromatography

This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation with multiple secondary retention times. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The secondary retention time period at which the modulator cycles is variable among multiple secondary retention time periods to prevent loss of resolution with less complex and/or low boiling point compounds and to prevent loss of data with more complex and/or higher boiling point compounds. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Partial modulation via pulsed flow modulator for comprehensive two-dimensional liquid or gas chromatography with multiple modulation periods

The adaptive temperature controller includes an ambient temperature sensor, a device for measuring resistance, an electrically-conductive material, a power supply, and a device for controlling power. In operation, the controller determines the resistance of material at or near ambient temperature. Based on such determination so long as voltage and power are known, the resistance of the material, and therefore its instant temperature is known. Additionally, the adaptive temperature controller determines the responsiveness of the electrically-conductive material to determine the predicted increase in temperature and rate of increase in temperature relative to increases in voltage, current or power. As a result the voltage or power may be instantly varied to produce near infinite control over material temperature.

Partial modulation via pulsed flow modulator for comprehensive two-dimensional liquid or gas chromatography

A pulsed discharge detector includes a device and method for modular measurement of ionization signals from a sample. The pulsed discharge detector includes a discharge source in a chamber, a collector spaced from the discharge source, a monitor connected to a discharge electrode, an electrometer connected to the collector, a calibrator and a sample and hold processor. The discharge electrodes include a source electrode centrally located in relation to the discharge chamber wall. The collector is centrally located in relation to the chamber wall. Discharge signals are monitored for time and intensity. Collected signals are adjusted based on the discharge intensity. Collected signals are collected during a time window based on the discharge occurrence time. Detector output is predicated on collected signals coordinated with pulsed discharges. The calibrator of the present invention adjusts the collected signals to reduce discharge noise. The sample and hold processor accumulates selected adjusted signal values to quantify sample concentrations.

Gas detector with modular detection and discharge source calibration

A detection system measures very small concentrations of compounds of interest within gaseous samples. A spark discharge system induces pulsed spark discharges across a pair of electrodes within an inert gas in a gas flow chamber. Various reactions are induced by spark interaction with the flow of inert gas, and with any sample or dopant commingled with the inert gas, in the region of the pulsed spark discharge. This induces photon ionization which creates an instantaneous current flow within the gas flow chamber. Current flow is held constant for all concentrations of sample introduced into the gas flow by means of a control feedback system. The output of the control feedback system is indicative of sample concentration. The system responds linearly over approximately five orders of magnitude of sample concentration for use with the sample which will be described and low femtogram sensitivity is achieved.

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Houston, TX, United States of America

Huamin Cai