1.0 SCOPE AND APPLICATION
1.1 This method is an acid digestion procedure for analysis of oils, oil sludges, tars,
waxes, paints, paint sludges and other viscous petroleum products for the sixteen toxic elements
listed below:
Antimony Arsenic Barium Beryllium
Cadmium Chromium Cobalt Copper
Lead Molybdenum Nickel Selenium
Silver Thallium Vanadium Zinc
Other elements and matrices may be analyzed by this method if performance is demonstrated for
the analytes of interest, in the matrix of interest, at the concentration levels of interest (see Section
8.0). The resulting digestate can be analyzed by either flame atomic absorption spectrometry
(FLAA), graphite furnace atomic absorption spectrometry (GFAA), or inductively coupled plasma
atomic emission spectrometry (ICP-AES).
1.2 The large concentration of manganese present in the digestate of Method 3031 can
interfere with the determination of low concentrations of arsenic which is important for the recycled
oil regulations. As an optional step, manganese may be removed from the digestate by forming a
manganese phosphate precipitate. The remaining liquid can be analyzed by either flame atomic
absorption spectrometry (FLAA) or inductively coupled plasma (ICP-AES). Chlorides can be
removed by the use of nitric acid for analysis by graphite furnace atomic absorption spectrometry
(GFAA) for arsenic. These clean-up procedures may be applicable to other elements as can be
demonstrated by appropriate procedures (Sec. 7.11).
2.0 SUMMARY OF METHOD
2.1 A representative 0.5 g sample is mixed with 0.5 g of finely ground potassium
permanganate and then 1.0 mL of concentrated sulfuric acid is added while stirring. A strong
exothermic reaction occurs. The sample is then treated with 2 mL concentrated nitric acid. 10 mL
of concentrated HCl is added and the sample is heated until the reaction is complete and is then
filtered. The filter is washed with hot concentrated HCl. The filter paper is transferred to a digestion
flask, treated with 5 mL of concentrated hydrochloric acid. The sample is brought to volume and
analyzed by ICP-AES or FLAA.
WARNING: THIS PROCEDURE SHOULD NOT BE ATTEMPTED BY INEXPERIENCED
PERSONNEL. MANY OF THE REACTIONS ARE STRONGLY EXOTHERMIC AND CAN
RESULT IN SPLATTERING OR IN THE GENERATION OF GASES. GLOVES,
FACESHIELDS, AND LAB COATS MUST BE WORN WHEN WORKING WITH ACIDS. IT
IS STRONGLY RECOMMENDED THAT THE ADDITION OF SULFURIC ACID BE
PERFORMED BEHIND A GLASS SHIELD OR SASH.