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Vessel Cleaning
Vessel Cleaning
WARNING
Proper precautions must be taken to avoid contact with acids or acid vapors. Protective gear should be
worn as outlined in the user’s safety program for hazardous materials and the acid manufacturer’s safety
data sheet. Refer to these guidelines for proper handling and disposal of the acids.
Liner
1.
Rinse the liners with deionized water and allow to dry completely before use.
2. If measuring ppm, ppb and/or ppt analyte levels, proceed with steps below.
3.
Clean liners with hot, soapy water and foam brush. Rinse thoroughly with deionized water and allow to dry
completely before use.
NOTE
Micro-90® cleaning solution works well on Teflon. Avoid detergents that contain ingredients that could
cause potential contamination such as Na and P. Avoid abrasive cleansers and stiff brushes which can
scratch the Teflon surface.
4.
Clean liners using the microwave as outlined below. All vessel components must be dry before use.
4.1.
Add 10 mL of acid type that had been used for sample digestion, HNO
3
, HCl, H
2
SO
4
, H
3
PO
4
or HF.
4.2.
Prepare vessel and turntable as outlined in manual.
4.3.
Select and run the "Easy Prep Clean" method in the One Touch directory.
4.4.
Wait for vessels to cool for a minimum of 15 minutes before opening microwave door.
4.5.
Discard acid and rinse the liners and covers with deionized water.
Liner Bake-out Procedure
As needed: The bake out procedure can be used to remove residual acid vapors and other trapped gases from the
Teflon® material. Trapped gases can potentially cause uneven heating between new and used liners.
The bake out procedure can be used to remove residual NOx gases from liners following digestion with HNO
3
that
may interfere in subsequent runs. This procedure has been successfully used to remove sulfur contamination from
the Teflon following digestion of samples with high sulfur content.
1.
Place the liners on their side in an air oven at room temperature.
CAUTION
Only the liners should be placed in the air oven at 180 ºC. Sleeves can be placed in an air oven no greater
than 105 °C. See "Sleeves" section for more detail.
2.
Set the oven temperature to 180 °C and let the liners warm slowly. Do not exceed an oven temperature of 190
°C.