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3. Hold the parts exposed to the digestion mixture under running water,
avoiding getting water or the digestion mixture into the heater base.
If the aspirator fails during a digestion, immediately turn the heater off.
Do not breathe any fumes that may be expelled from the manifold. After
the flask has cooled and the fumes subsided, clean or replace the
aspirator.
If the flask boils dry during the digestion, unplug the heater assembly
and allow the flask to cool. Remove the flask and discard the contents.
Repeat the digestion using less sample or more acid. If hydrogen
peroxide was added to the flask before it went dry, wait until the flask
cools completely. Add water to the flask before handling.
Chemicals
Concentrated sulfuric acid and hydrogen peroxide used in the digestion
process should be handled correctly and with caution. Sulfuric acid is a
strong acid and can cause burns if splashed on the skin and permanent
damage if eye contact occurs. Hydrogen peroxide (30% or 50%) is a
powerful oxidant and should never be stored near flammable materials.
Like sulfuric acid, it can cause burns and eye damage. In case of eye or
skin contact with either chemical, flush eyes and/or skin with water for
15 minutes. Remove contaminated clothing. Call a physician.
Both sulfuric acid and hydrogen peroxide are highly corrosive and
should be cleaned up with water if spilled on instruments or a counter
top. Read and observe all warnings on the reagent labels and Material
Safety Data Sheets (MSDS).
Proper handling and storage procedures involving hydrogen peroxide
should always address two major characteristics of the product: first, it is
a strong oxidizing agent (corrosive), and second, it can decompose,
releasing heat and oxygen. The chemical nature of hydrogen peroxide
makes it an irritant to the skin, to mucus membranes and particularly to
the eyes. It will cause chemical burns at industrial concentrations and
may cause spontaneous combustion upon immediate or prolonged
contact with combustibles.
Hydrogen peroxide decomposes to form water and oxygen. The natural
decomposition rate of the normal industrial grade product is very low,
but it will accelerate when contaminated by materials such as dust,
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