Multi-capillary column pre-concentration system for enhanced sensitivity in gas chromatography (GC) and gas chromatography-mass spectrometry (GCMS)

A method of pre-concentrating a sample before chemical analysis, the method comprising:

• during an adsorption process of a first trap, the first trap comprising a first primary capillary column, a second primary capillary column, and a third primary capillary column connected in series with increasing affinity, during which the first primary capillary column of the first trap, the second primary capillary column of the first trap, and the third primary capillary column of the first trap are a at an adsorption temperature between 20 and 50 degrees Celsius:
• facilitating, via one or more valves, the sample to flow through the first primary capillary column of the first trap, the second primary capillary column of the first trap, and the third primary capillary column of the first trap in a first direction, the first direction being from the first primary capillary column to the third primary capillary column;
• and
• during a desorption process:
• facilitating, via the plurality of valves, a desorption gas to flow through the first primary capillary column, the second primary capillary column, and the third primary capillary column in a second direction, the second direction being from the third primary capillary column to the first primary capillary column,
• wherein:
• the first primary capillary column has an interior surface coated by a first sorbent, the first primary capillary column with the first sorbent having a first affinity for one or more compounds of the sample, the first primary capillary column having a length between 0.2 and 5 meters,
• the second primary capillary column has an interior surface coated by a second sorbent, the second sorbent having a higher affinity for the one or more compounds than an affinity the first sorbent has for the one or more compounds, the second primary capillary column with the second sorbent having a second affinity for the one or more compounds of the sample, the second affinity greater than the first affinity, the second primary capillary column having a length between 0.2 and 5 meters,
• the third primary capillary column has an interior surface coated by a third sorbent, the third sorbent having a higher affinity for the one or more compounds than the affinity the second sorbent has for the one or more compounds, the third primary capillary column with the third sorbent having a third affinity for the one or more compounds of the sample, the third affinity greater than the first affinity, the third primary capillary column having a length between 0.2 and 5 meters, and
• the first primary capillary column, the second primary capillary column, and the third primary capillary column are coupled in series.

A system comprising:

• a sample container containing a sample;
• a first trap, the first trap comprising a first primary capillary column, a second primary capillary column, and a third primary capillary column connected in series with increasing affinity, wherein:
• the first primary capillary column has an interior surface coated by a first sorbent, the first primary capillary column having a length between 0.2 and 5 meters, the first primary capillary column with the first sorbent having a first affinity for one or more compounds of the sample, wherein the first primary capillary column having the interior surface coated by the first sorbent is configured to adsorb one or more compounds while the first primary capillary column has a temperature between 20 and 50 degrees Celsius;
• the second primary capillary column has an interior surface coated by a second sorbent, the second sorbent having a higher affinity for the one or more compounds than an affinity the first sorbent has for the one or more compounds, the second primary capillary column having a length between 0.2 and 5 meters, the second primary capillary column with the second sorbent having a second affinity for the one or more compounds of the sample, the second affinity greater than the first affinity, wherein the second primary capillary column having the interior surface coated by the second sorbent is configured to adsorb one or more compounds while the second primary capillary column has a temperature between 20 and 50 degrees Celsius;
• the third primary capillary column has an interior surface coated by a third sorbent, the third sorbent having a higher affinity for the one or more compounds than the affinity the second sorbent has for the one or more compounds, the third primary capillary column having a length between 0.2 and 5 meters, the third primary capillary column with the third sorbent having a third affinity for the one or more compounds of the sample, the third affinity greater than the second affinity, wherein the second primary capillary column is coupled between the first primary capillary column and the third primary capillary column in series, wherein the third primary capillary column having the interior surface coated by the third sorbent is configured to adsorb one or more compounds while the third primary capillary column has a temperature between 20 and 50 degrees Celsius;
• a chemical analysis device, the chemical analysis device comprising a detector configured to detect one or more compounds of the sample;
• and
• one or more valves fluidly coupling the first trap to the sample container, the one or more valves configured to:
• during an adsorption process during which the first primary capillary column, the second primary capillary column, and the third primary capillary column are at an adsorption temperature between 20 and 50 degrees Celsius, facilitate the sample to flow from the sample container through the first primary capillary column, the second primary capillary column, and the third primary capillary column in a first direction, the first direction being from the first primary capillary column to the third primary capillary column, and
• during a desorption process, facilitate a desorption gas to flow through the first primary capillary column, the second primary capillary column, and the third primary capillary column in a second direction, the second direction being from the third primary capillary column to the first primary capillary column and towards the chemical analysis device.