How can I avoid failing Residual Solvents Analysis?

The following are considerations that may help you prevent failing for residual solvents:

  • Ensure you are purging completely by getting a residual solvent R&D test before submitting the full I-502 sample. The extra cost is worth saving the headache of having to get LCB approval to re-purge and re-test the lot. You can always check your purge by sending in a quick sample. We can usually turn those results within one day.
  • Maintain your purge system effectively. Monitor the actual pressure inside your vacuum oven, instead of assuming that the system is operating as it should. Even a small air leak can result in a lot failure. Remember: vacuum gauges are typically unreliable when the needle is near the extremes of the graduations.
  • Consider producing the honeycomb wax consistency instead of the shatter or sugar consistency, as the much higher surface area of the foam (honeycomb wax) enables a faster and more thorough purge. Several processors that test with us routinely come in less than 10 ppm by using the honeycomb wax method.
  • Unless you have a vacuum oven with absolutely perfect seals (and none are perfect, so don’t kid yourself), do not turn off the vacuum pump during purge to save pump life or energy. As a general rule: you’re only purging when your pump is pumping. Also keep an eye on pump oil levels and condition of any pump seals that may fail.
  • Increasing the heat level won’t necessarily decrease your purge time. Melting down the slab (as compared to allowing it to have bubbles) reduces its surface area, slowing down purge. The more bubbles the slab can maintain, and the smaller those bubbles, the more efficient the purge will be. It is important to watch the slab/muffin, and make sure that each slab behaves as expected. Melting down too rapidly may cause more solvent retention.
  • Consider solventless extraction (traditional hashish, “rosin technique”) or alternative solvents (CO2, ethanol).