Coupling the TGA to the Mass Spec

This manual is meant to complement your training and is not intended to replace on-the-job training.

Last Updated

5/4/2015

OPERATING PROCEDURE

Attaching the Mass Spec:

  • Remove the mass spec attachment from its box. Carefully remove the screws securing the top cover to the bottom plate. Hold the two pieces together while you remove the screws so that you do not break the capillary. Carefully remove the capillary housing from the metal case and set it aside where it will be safe.

  • Use the black hex screws to attach the base plate to the side of the TGA furnace. Remove the yellow plug.

  • Check the end of the capillary coming out of the housing. Make sure it is not discolored (it should be a faintly gold colored) and that the end is not a jagged break but a clean cut. If there is discoloration in the first few inches, use the capillary cutting tool to score the capillary and gently bend the capillary at the score to break off the discolored portion. Check your new break to be sure it's good.

  • Use your fingers to gently guide the capillary into the hole in the metal adapter on the furnace. Simply pushing on the black housing is not sufficient - that will usually just cause the capillary to push back into its housing.

  • Aim to get the capillary inserted so that it gets as close to the inner chamber of the furnace as possible without entering into it.

  • When you think the capillary is in the right place, hold the capillary in place and push the black housing up to meet the metal adapter. There is a smaller inner white tube which should nestle into the depression in the metal adapter.

  • While holding the housing with one hand, place the cover on top, then hold the cover down to hold the black rubber capillary housing in place while you put in one screw to hold the cover on.

  • Use the mirror and LED light to VERY CAREFULLY look into the furnace and make sure you cannot see any of the capillary sticking into the furnace. You must be incredibly careful with the mirror so that you do not bump the hang-down hook while looking into the furnace. Hold the mirror as close to the opening of the furnace as possible and always keep one eye on the hang-down hook when moving the mirror.

  • If you do not see any capillary extending into the furnace, you can screw the cover down the rest of the way. Three screws is enough, both front screws and the back left one. Trying to get the back right screw in can sometimes cause you to hit the hang-down hook with your right hand, so I recommend that you don't insert that screw.

You are now ready to run the mass spec.

Removing the Mass Spec:

Before attempting this procedure, turn off the Evolved Gas Heater in the TGA Software!!!

  • Hold the cover down with one hand while removing the cover screws with your other hand.

    • Hold the black capillary housing in place with one hand while lifting the cover off of the housing. Be careful not to let the capillary housing life from the base plate, which could cause the capillary to break off in the metal adapter.

    • Pull the capillary housing straight back away from the metal adapter to pull the capillary out of the TGA furnace.

    • Unscrew the base plate with the hex driver.

    • Reassemble the capillary housing between the base plate and cover. Use at least two screws to secure the case around the capillary housing.

    • Carefully place the entire assembly back into the foam lined box, being careful not to break the capillary in the box.

    • Once the metal adapter is fully cooled (you remembered to turn off the Evolved Gas Heater in the TGA software, right???), replace the yellow plug.

Common Problems:

Your pan falls off the hang-down hook into the furnace:

Immediately notify Alyssa. She can remove your pan from the furnace in about 5 minutes. If you try to retrieve the pan yourself, you will most likely destroy the hang-down hook and never get the pan out anyway.

The capillary was probably extending into the inner chamber of the furnace. Sometimes, even if you have the capillary lined up correctly when you put on the cover, the capillary can move slightly afterward. You will have to readjust the capillary position.

The weight of your pan is incredibly noisy or fluctuates wildly between high and low values:

Again, the capillary is probably extending into the inner chamber of the furnace, but just enough to touch the side of your pan a little bit. You will have to unload your pan and readjust the capillary.

The capillary breaks off in the metal adapter:

Notify Alyssa. The metal adapter can be removed but it's tricky to put back on. Please don't try to fix it yourself. Please don't push the broken piece of capillary into the furnace.