University of Michigan

Hongbo Zhu

Xudong Fan

Katsuo Kurabayashi

Menglian Zhou

Jiwon Lee

Robert Nidetz

Jinyan She

Maxwell Wei-Hao Li

A gas chromatography device for peak focusing of one or more target analytes is provided that include a chromatographic column with an inlet and an outlet. A stationary phase is deposited inside the chromatographic column and has a positive thickness gradient. The stationary phase extends from the inlet to the outlet and has a first thickness at the inlet of the chromatographic column and a second thickness at the outlet of the chromatographic column. The second thickness is at least about 10% greater than the first thickness. Methods of peak focusing in a gas chromatography device, method of verifying peak focusing in a gas chromatography device and creating a gas chromatography device having a chromatographic column with a positive thickness gradient are also provided.

Chromatographic column having stationary phase thickness gradient

An integrated microfluidic photoionization detector (PID) is provided including a microfluidic ionization chamber a microfluidic ultraviolet radiation chamber that is configured to generate ultraviolet photons. An ultrathin transmissive window is disposed between the microfluidic ionization chamber and the microfluidic ultraviolet radiation chamber that permits the ultraviolet photons to pass from the microfluidic ultraviolet radiation chamber into the microfluidic ionization chamber. Detection systems for one or more VOC analytes are also provided that include a gas chromatography (GC) unit including at least one gas chromatography column and an integrated microfluidic photoionization detector (PID) disposed downstream of the gas chromatography (GC) unit.

Integrated micro-photoionization detector with an ultrathin ultraviolet transmission window

The present disclosure provides a method for conducting comprehensive chromatography analysis. Broadly, the method comprises separating a sample in a first chromatographic column to generate a primary stream, which is directed toward a non-modulator switching system comprising at least one micro-switch and at least one valve. The non-modulator switching system is continuously operated to: (a) selectively direct a portion of the primary stream to one of a plurality of thermal injectors and accumulating the portion of the primary stream for a predetermined amount of time; (b) inject the portion of the primary stream into one of a plurality of secondary chromatographic columns; (c) detect one or more analytes in a secondary stream exiting the secondary chromatographic column; and repeat (a)-(c) to selectively direct other portions of the primary stream to other thermal injectors and secondary chromatographic columns until all of the analytes in the sample are detected.

Multi-channel multi-dimensional comprehensive gas chromatography

A discharge ionization current detector for ionizing and detecting a sample component where the sample component is ionized by UV light is provided. The detector includes a UV light source, and a microfluidic channel having a first surface including a conducting or semiconducting material and an opposing second surface including a conducting or semiconducting material, one of the first surface and the second surface being a collection electrode and the other of the first surface and the second surface being a bias electrode, the microfluidic channel being configured to receive a sample component. The microfluidic channel is in fluid communication with the UV light source such that, when activated, UV light from the UV light source can enter the microfluidic channel and ionize the sample component, which releases an electron, and the ionized sample component and electron are detected by the collection and bias electrodes.

Miniaturized discharge photo-ionization detector

A rapid flow-through, highly sensitive microfluidic photoionization detector (PID) which is micro-fabricated directly onto a substrate, such as a conductive silicon wafer, is provided. The microfluidic PID has an ionization chamber volume of less than 9 &#x3bc;L. The microfluidic PID may have a flow through design with a microfluidic channel defines a serpentine pattern on the substrate. The flow through design of the microfluidic PID results in negligible dead volume, thus allowing a shortened response time over existing commercially available designs. Such microfluidic PIDs are particularly useful with gas chromatography (GC), including microGC and multi-dimensional microGC systems. Methods for calibrating PIDs are also provided.

Growing community of inventors

Ann Arbor, MI, United States of America

Hongbo Zhu