Soil organic matter density fractionation devices and methods

An extractor module for a fractionation system, the extractor module comprising:

• an extractor assembly having an extractor nozzle disposed at a distal end of a conduit, the extractor nozzle configured to be inserted into a soil sample having a light soil fraction suspended above a heavy soil fraction;
• a filter assembly having first and second sealing members, the first sealing member fluidly coupled to a first tube and the second sealing member fluidly coupled to a vacuum chamber;
• a first linear actuator configured for relative movement of the extractor assembly;
• and
• and a second linear actuator configured for relative movement of the filter assembly.

A method of separating soil fractions, the method comprising:

• moving a first sample rack having a sample tube and a filter cup into an extractor module;
• inserting an extractor nozzle into the sample tube, the sample tube having a first soil fraction suspended above a second soil fraction;
• moving a first sealing member into engagement with a top of a filter cup and moving a second sealing member into engagement with a bottom of the filter cup;
• forming a vacuum within the filter cup;
• transferring via the vacuum the first soil fraction from the sample tube to the filter cup through a conduit that fluidly couples the extractor nozzle to the first sealing member;
• removing the extractor nozzle from the sample tube and disengaging the first and second sealing members from the filter cup;
• and
• moving a second sample rack into the extractor module.