CEM BLADE - Vessel Cleaning; Percent (%) to PPM Level - DI Water Rinse; Low PPM Level - 10 % Acid Soak; PPB Level - Microwave Clean Run

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Vessel Cleaning
Vessel Cleaning
Vessel cleaning after microwave digestion is performed to minimize or eliminate cross contamination from sample
to sample. The spectroscopic technique used, and level of analytes reported, will dictate how clean your vessels
should be. CEM recommends the following cleaning protocols based on level of analysis but each lab must
determine their own cleaning protocol. Running method blanks will help determine if the cleaning protocol is
sufcient.
If physical debris or residue is remaining, then soaking and washing vessels with a phosphate free laboratory
detergent (ex. Micro-90 or Citranox) is recommended. Thoroughly rinse with deionized water and then proceed to
suggested cleaning techniques as related to level of analysis.
Organic solvents can be used to removed residue as needed. Once removed, follow the recommended soap clean
as outline above.
Percent (%) to PPM Level – DI Water Rinse
For analysis in the percent level (ex. Al = 25% of composition) to mid/high ppm level (ex. 100 ppm Al) rinsing
vessels with deionized water may be sufcient to prevent signicant carryover between runs. The use of ACS
Reagent Grade acids is usually acceptable for digestions.
Low PPM Level – 10 % Acid Soak
For analysis in the low ppm level (ex. 0.5 ppm Al) soaking for a minimum of 10 minutes in 10% acid followed by
deionized water rinse may be sufcient. The use of ACS Trace Metal Grade acids is usually acceptable for cleaning
and digestions.
PPB Level – Microwave Clean Run
For analysis at or below the 100 ppb level, a microwave clean run, using the acid mixture used for the analysis
followed by deionized water rinse is recommended. The use of ACS Trace Metal Grade or distilled acids is usually
acceptable for cleaning and digestions.
Sub PPB Level– Multiple Microwave Clean Runs
For sub ppb level analysis, 2-3 microwave clean runs may be required. Ultra Pure acids are required for cleaning
and digestions at these levels.
If the above methods do not sufciently clean your vessels contact Elemental.Support@cem.com and ask for the
“Microwave Chelating Method”.
General Notes
• Check the lot analysis for each acid to ensure that the level of metals impurity is acceptable for your analytes of
interest.
• Always store vessel components in plastic, or other non-metallic, containers to minimize contamination from
storage. For low level ppm and lower work it is recommended to store vessels in covered-plastic bins.