Method And Apparatus For Concentrating Vapors For Analysis

• US 20080302237A1
• Filed: 08/08/2008
• Published: 12/11/2008
• Est. Priority Date: 02/08/2006
• Status: Active Grant

• Current Assignee: David L. Baldwin, Jay W. Grate, Norman C. Anheier Jr
• Original Assignee: David L. Baldwin, Jay W. Grate, Norman C. Anheier Jr
• Inventors: Grate, Jay W., Anheier, Norman C. JR., Baldwin, David L.
• Granted Patent: US 8,191,435 B2
• Time in Patent Office: Days
• US Class Current: 95/18
• CPC Class Codes: G01N 1/2214 by sorption
• CPC Class Codes: G01N 1/405 by adsorption or absorption
• CPC Class Codes: G01N 2030/126 evaporating sample
• CPC Class Codes: G01N 30/12 by evaporation

Abstract

A pre-concentration device and a method are disclosed for concentrating gaseous vapors for analysis. Vapors sorbed and concentrated within the bed of the pre-concentration device are thermally desorbed, achieving at least partial separation of the vapor mixtures. The pre-concentration device is suitable, e.g., for pre-concentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable.

Claims

1. A method for performing analysis of gaseous mixtures, characterized by the steps of:

providing a conduit having at least one inlet and one outlet for flowing one or more vapors in a gaseous volume therethrough, said conduit containing a sorbent disposed upon a metal foam for concentrating vapors from said gaseous volume by sorption, and releasing concentrated vapors by desorption;

sorbing said one or more vapors on said sorbent thereby concentrating said one or more vapors; and

heating said sorbent to a temperature sufficient to desorb said one or more concentrated vapors therefrom, said desorption generating a response in a detector of sufficient sensitivity for detection and/or analysis of said one or more concentrated vapors.

2. The method of claim 1, wherein said sorbent is selected from the group consisting of Tenax®

, Carbotrap, Carboxen, Carbosieve, carbon nanotubes, glass bead, polymers, molecular sieves, activated carbons, ceramics, Aluminas, Silicas, silica gels, polars, dessicants, and combinations thereof.

3. The method of claim 1, wherein the sorption of said one or more vapors comprises flowing said gaseous volume through said conduit at a rate in the range from about 1 mL/min to about 10,000 mL/min.

4. The method of claim 1, wherein the step of heating said sorbent is performed using a heater and a temperature sensor operatively disposed within said conduit for effecting controlled thermal desorption of said one or more vapors that provides at least partial separation of said one or more vapors.

5. The method of claim 1, wherein the thermal desorption of said one or more vapors is performed using temperature programming and/or thermal ramping.