The present disclosure relates generally to systems for separating chemical compounds via two-dimensional gas chromatography. Certain embodiments of the system are configured to rapidly heat and cool the second dimension column by a unique arrangement of heating and cooling elements.

The present disclosure relates generally to processes for separating chemical compounds via two-dimensional gas chromatography. Certain embodiments comprise rapid heating and cooling of the second dimension column by a unique arrangement of heating and cooling elements.

The present disclosure relates generally to processes for separating chemical compounds via two-dimensional gas chromatography. Certain embodiments comprise rapid heating and cooling of the second dimension column by a unique arrangement of heating and cooling elements.

In a method for processing successive fluidic sample portions provided by a sample source, sample reception volumes are filled successively temporarily with at least a respective one of the sample sections, and the sample sections are emptied successively out of the sample reception volumes in such a way, that, while emptying, it is avoided to bring two respective ones of the sample sections, which have not left the sample source directly adjacent to one another, in contact with one another.

The invention discloses a flow control block for a stack of chromatography column modules, as well as a stack of chromatography modules comprising at least one flow control block. The flow control block is in a first position or configuration capable of connecting two chromatography column modules, or a chromatography column module and an endpiece, in parallel and in a second position or configuration it is capable of connecting two chromatography column modules, or a chromatography column module and an endpiece, in series.

A gas chromatographic method for detecting a marker compound in a fuel by (a) introducing a sample of fuel into a first capillary column coated with a stationary phase based on polydimethylsiloxane and allowing the sample to flow through the first column to produce a first effluent; (b) allowing the first effluent to pass through a detector and identifying a retention time range in it which includes a retention time of the marker compound; (c) introducing only a portion of the first effluent stream which is within the retention time range into a second capillary column coated with either (i) an ionic sorbent or (ii) a polyethylene glycol, and allowing said portion to flow through the second capillary column to produce a second effluent stream; and (d) allowing the second effluent to pass through a detector; wherein the marker compound has formula Ar(R.sup.2).sub.m(OR.sup.1).sub.n and is present in the fuel at a level from 0.01 ppm to 100 ppm.

Described is a rotary valve that includes a stator, a rotor and a plurality of sample channels. The stator includes a stator surface having an inlet port, an outlet port and a plurality of selectable ports. The rotor includes a rotor surface having a first rotor channel and a second rotor channel. The rotor is configurable in a plurality of rotor positions, each of which couples the inlet port to one of the selectable ports through the first rotor channel and couples the outlet port to another one of the selectable ports through the second rotor channel. The two selectable ports are coupled to each other through one of the sample channels. The rotor has a bypass state defined by a rotor position, or angular range of rotor positions, at which the inlet port is coupled to the outlet port through the second rotor channel.

A sample separation apparatus for separating a fluidic sample includes an initial dimension sample separation device configured for separating the fluidic sample, a subsequent dimension sample separation device configured for further separating separated fluidic sample received from the initial dimension sample separation device, a purity detector configured for detecting information indicative of a purity of a portion of the fluidic sample which has been separated by the initial dimension sample separation device, and a control unit configured for controlling, depending on the detected information, whether or not further separation of the portion of the fluidic sample which has been separated by the initial dimension sample separation device is carried out by the subsequent dimension sample separation device.

A fluid transfer valve has ports arranged in groups. The valve has a rotor having channels and an actuator is operably connectable to the rotor. The actuator is positionable in a loading orientation in which the first channel is connected to one or two of the ports to transfer fluid into the first channel and/or the second channel is connected to one or two of the ports to transfer a second fluid into the second channel. The actuator also is positionable into first and second injection orientations in which various ones of the channels and ports are connected for different fluid flow configurations. Each channel has two ends located on a virtual circle whose center coincides with the rotor's axis of rotation. The channels can have a semicircular shape, a semi-oval shape or a U-shape. An analytical system and method that use the inventive valve are also disclosed.

A thermal modulator for a chromatographic system includes a cooler, a thermal valve, a thermal buffer, a heater, and a capillary. The thermal valve thermally-engages the cooler. The thermal buffer thermally-engages the thermal valve. The heater thermally-engages the thermal buffer. The capillary thermally-engages the heater and is configured to transport an analyte in a first direction.