A thermal desorption tube collection system uses a thermoelectric cooler to collect and concentrate gas samples. In some modes, the operation of the cooler is reversed to flow the concentrated sample directly into a separator such as a gas chromatography system. Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. Also presented are methods for analyzing biogas samples.

The disclosed system and method improve measurement of trace volatile chemicals, such as by Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GCMS). A first trapping system can include a plurality of capillary columns in series and a focusing column fluidly coupled to a first detector. The first trapping system can retain and separate compounds in a sample, including C3 hydrocarbons and compounds heavier than C3 hydrocarbons (e.g., up to C12 hydrocarbons, or compounds having a boiling point around 250 C.), and can transfer the compounds from the focusing column to the first detector. A second trapping system can receive compounds that the first trapping system does not retain, and can include a packed trap, a polar column and a PLOT column fluidly coupled to one or more second detectors. The second trapping system can remove water from the sample and can separate and detect compounds including C2 hydrocarbons and Formaldehyde.

The invention is a method for estimating a retention time of a particle in a chromatography column, and more particularly in a chromatography column one parameter of which, such as temperature, is modulated. The retention time is estimated on a probabilistic basis by sequentially modelling the transit of the particle in the column. When this stochastic approach is adopted for a set of particles of a given type, it allows a statistical distribution of the retention time in the column to be determined.

A crescent PLOT column is disclosed, including a capillary column having an inlet, an outlet, a bore, and an inner surface surrounding the bore and extending between the inlet and the outlet. A layer of particles is localized on a radial portion of the inner surface. The layer of the particles includes a radial thickness decreasing from a center of the radial portion to a periphery of the radial portion, forming a crescent shape in a radial frame of reference. A method for preparing the crescent PLOT column is disclosed, including loading the capillary column with a fluid including a carrier and particles such that the fluid is contained within the capillary column. The capillary column and the fluid contained within the capillary column are subjected to a centrifugal force. The carrier is removed, and a layer of the particles is localized on the radial portion of the inner surface.

A multi-walled tube that is useful as an analytical column in which chemical mixtures can be separated into their individual components is described. In order to be acceptable as an analytical column, the inner surface of the multi-walled tube must support effective separation, but not react chemically with or contaminate the solvent or the analyte (sample to be separated). Grade 316 stainless steel is typically preferred for this purpose. Moreover, the inner diameter (ID) surface of the multi-walled column is preferably very smooth (less than 10 micro inch Ra) with no interruptions in the surface such as scratches, pits, or asperities. However, since the column is designed to be attached to chromatographic equipment using standard size connection features, the size of standard fittings define the outer diameter (OD) of the column.

An open tubular chromatography apparatus has at least one liquid chromatography capillary, a valve in fluid communication with the liquid chromatography capillary for adding a sample to the liquid chromatography capillary, an injector in fluid communication with the valve for driving liquid eluent through the liquid chromatography capillary whereby components of the sample are separated in the eluent, and one or more detectors for detecting the components in the sample as the components elute from the liquid chromatography capillary. The liquid chromatography capillary has an inner surface and an inner diameter in a range of from about 1 m to about 5 m. The inner surface is coated with a stationary phase film.

In an aspect, a method for forming a microcolumn comprises steps of: (a) providing a sacrificial fiber; (b) forming a microcolumn body around said sacrificial fiber; and (c) removing said sacrificial fiber from said microcolumn body such that a hollow channel is formed within said microcolumn body via removal of said sacrificial fiber. In any embodiment of the methods disclosed herein for forming a microcolumn, said hollow channel extends through said microcolumn body and is continuous between a first end and a second end. The first end may be an inlet and the second end may be an outlet, for example, allowing for a mobile phase to enter the hollow channel via the first end and exit via the second end.

Exemplary embodiments are directed to devices for separating a sample by chromatography, components of the devices, and methods for using the devices, and directed to devices and components for use with immobilized enzymatic reactors. A device includes a wall having a wetted surface exposed to a mobile phase including the sample during chromatographic separation. The wetted surface of the wall includes an alloy material including the following constituents: nickel, and cobalt and/or chromium where the alloy is limited in an amount of titanium to 1 wt %. A component includes a body having a wetted surface exposed to a mobile phase including the sample during chromatographic separation. The wetted surface of the body includes an alloy material including the following constituents: nickel, and cobalt and/or chromium where the alloy is limited in an amount of titanium to 1 wt %.

A multi-walled tube that is useful as an analytical column in which chemical mixtures can be separated into their individual components is described. In order to be acceptable as an analytical column, the inner surface of the multi-walled tube must support effective separation, but not react chemically with or contaminate the solvent or the analyte (sample to be separated). Grade 316 stainless steel is typically preferred for this purpose. Moreover, the inner diameter (ID) surface of the multi-walled column is preferably very smooth (less than 10 micro inch Ra) with no interruptions in the surface such as scratches, pits, or asperities. However, since the column is designed to be attached to chromatographic equipment using standard size connection features, the size of standard fittings define the outer diameter (OD) of the column.

A biocompatible tube and fitting system that can be used in a liquid chromatography system is described. The tube can have a polymer tip and can be used in conjunction with one or more fitting assembly.