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.

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.

Certain embodiments described herein are directed to chromatography systems that include a microfluidic device and that implement one or more methods to direct sample to a desired fluid flow path. The methods can be used to backflush a sample to a desired fluid flow path to select certain analytes within a sample.

Embodiments of multi-column gas chromatography for analysis of a formation sample are disclosed. In one embodiment, an apparatus comprises a gas chromatography instrument and a controller. The gas chromatography instrument comprises a sample injector; a primary column to separate out a hydrocarbon subset; a secondary column valve coupled to the primary column; a primary detector configured to analyze the hydrocarbons of the subset; a heart cutting unit coupled to the secondary column valve and configured to cut, from the subset, at least one isomer having a weight greater than a threshold; a secondary column coupled to an output of the heart cutting unit configured to separate out the at least one isomer; and a secondary detector configured to analyze the at least one isomer. The controller controls the secondary column valve to output the hydrocarbons to the heart cutting unit in response to at least one trigger event.