Safety Practices and Hazards
16 Agilent 55B AA Spectrometer User’s Guide
Never pass acetylene through copper or brass tubing, or fittings containing
more than 65% copper, since this may provoke an explosion.
Never bring acetylene into direct contact with copper, silver, liquid mercury,
gaseous chlorine or grease, as an explosion could result.
Use only acetylene that is packed in acetone with the Agilent 55B AA system.
Some gas suppliers offer acetylene packed in material other than acetone. While
these alternatives may overcome some of the disadvantages of acetone, they may
also introduce the more serious problem of corrosion in the Gas Control module
and must not be used with Agilent atomic absorption spectrometers.
If the pressure in the acetylene cylinder falls below 700 kPa (100 psig), or the
consumption is greater than 1/7 of the cylinder contents per hour, acetone may be
carried over from the cylinder and into the spectrometer. Acetone in the
spectrometer can damage seals, O-rings and hoses, degrade analytical
performance and precipitate flashbacks.
Minimize the amount of acetone which is carried over with the acetylene by:
Replacing cylinders when their contents pressure drops below 700 kPa
(100 psi).
Ensuring that the rate of acetylene drawn off from each cylinder is not
excessive.
If high rates of consumption are observed, then connect two or more cylinders in
parallel to a manifold. This will reduce the rate at which acetylene is drawn from
each cylinder.
To reduce the possibility of fire or explosion:
Test the supply ‘plumbing’ regularly for leaks with a brush and soapy water or
a proprietary leak-detecting solution (never use a naked flame when testing for
leaks).
‘Crack’ the cylinder before use by gently opening the valve to check for any
drops or spray of acetone. Any cylinder showing acetone should be returned
to the supplier for replacement.
Use ‘Instrument Grade’ acetylene that is at least 99.5% pure.
Turn off fuel gas at the cylinder when you have finished your flame analysis.
Refer also to your local regulations governing the use of acetylene.
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