Category: Sample preparation
Sub-category: Cryogenic work

Plunge freezing and instrument certification for SPT Labtech Chameleon.


You must complete all required safety training at the center you are visiting before hands on training. Coordinate this with the user office or training coordinator.


Relevant Training Modules (to review until you can pass the knowledge test):

SOP for Chameleon (for review before demonstration)

  • Printable version of the SOP
  • Digital version of the SOP

Vendor product information for reference

Additional reading:

The pass/fail knowledge assessment will test understanding of the following concepts:

  • How chameleon differs from other automatic plunge freezers.
  • Identify components of the instrument.
  • Proper operation and cleanup of the instrument.
  • Unique precautions to be taken with chameleon grids.
  • Evaluating images taken during plunging.
  • Parameters that can be altered to optimize sample dispensing on a grid.

Here is the current quiz version:

A workflow demonstration should be scheduled with center staff. The demonstration will cover all points of the SOP. You must have passed the knowledge quiz and reviewed the SOP before the demonstration.

Each center has additional specific Safety, Setup, and Shutdown procedures. Below, you will find those protocols for each center.

  • PNCC Site Specific Protocols – Chameleon
  • NCCAT Site Specific Protcols – Chameleon
  • S2C2 Site Specific Protocols – Chameleon

Schedule your supervised practice with the user office or appointed user coordinator. This can be scheduled for the same session as the demonstration. During supervised practice, center staff will be present for the full duration of the session to provide feedback and answer questions with the goal that you can pass the practical test for independence with no assistance. The number of supervised practice sessions will be tailored to the user, and if necessary, more than one session can be scheduled before taking the practical test.

Center staff will assist in arranging time for access to the necessary equipment and testing for independence. The practical test can not be scheduled during the same session as supervised practice.

A Chameleon independence checklist will be used by the certifying staff to test for proper use of the instrument with a pass/fail outcome. All steps on the checklist must be performed to pass. You may use any instructions normally posted as a guide during the session.

Additional information:

Recertification period

  • Sample preparation merit badges for cryogenic work are valid for ~6mo.
  • Recertification (to maintain active status) would entail demonstrating proper use and care in front of a center staff member.