INTERIM METHOD FOR THE ANALYSIS,OF ELEMENTAL PRIORITY POLLUTANTS r IN SLUDGE Vl (EMSL-CINCINNATI, DECEMBER 1978) The described digestion procedure is for preparation of sludge samples prior to required analysis by atomic absorption. With the exception of mercury, which uses an acid-permanganate digestion previous to cold vapor analysis, this digestion is applicable to both direct aspiration or furnace analysis of all other elemental priority pollutants. These pollutants are as follow: antimony (Sb). arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), selen- ium (Se), silver (Ag), thallium (Tl), and zinc (Zn}. DIGESTION PROCEDURE Weigh and transfer to a 125 ml conical Phillips' beaker a 1.0 gram portion of sample which has been dried at 60°C, pulverized, and thoroughly mixed. Add 5 ml of 1:1 nitric acid (HNO3) and cover with a watch glass. Heat the sample at 95°C and reflux to near dryness. Allow the sample to cool, add 4 ml of conc. HNO3 anc' again reflux to near dryness. After the second reflux step has been completed and the sample has cooled, add 1 ml of 1:1 HNO3 and 3 ml of 30^ hydrogen peroxide (H2O2). Return the beaker to the hot plate for warming to start the peroxide reaction. Care must be taken with the start of effer- vescence that losses do not occur or the reaction is not too vigorous. Heat until effervescence subsides and cool the beaker. Continue the addition of 30% H2O2 in 1 ml aliquots with warming until the effer- vescence is minimal or the general sample appearance is unchanged. (Note: do not add more than a total of 10 ml 30% H2O2)• (a) If the sample is being prepared for the furnace analysis of Sb and/or direct aspiration analysis of Sb, Be, Cd, Cr, Cu, Pb, Ni, and Zn, add 2 ml of 1:1 HC1, return the covered beaker to the hot plate and reflux for an additional 10 min. After cooling, filter through Whatman No. 42 filter paper (or equivalent) and dilute to 50 ml with deionized distil 1ed water. The sample is now ready for analysis. (b) If the sample is being prepared for the furnace analysis of As, Be, Cd, Cr, Cu, Pb, Ni, Se, Ag, Tl, and Zn, or the direct aspiration analysis of Ag and Tl, add 1 ml of 1:1 HNO3, return the covered beaker to the hot plate and reflux for an additional 10 min. After cooling, filter through Whatman No. 42 filter paper (or equivalent) and dilute to 50 ml with deionized distilled water. To prepare the analysis solution, withdraw an aliquot, add any required reagent or matrix modifier and dilute with deionized distilled water to twice the volume of the aliquot withdrawn. The sample is now diluted in IX (V/V) HNO3 and ready for analysis. ------- i 1-'! /'i /r l y 11 i -* ANALYSIS PROCEDURE (Atomic Absorption) For both direct aspiration and furnace analyses procedures, including the use of methods of standard additions, preparation of standard solutions, notes on interferences, instructions on the addition of required reagents or matrix modifiers, and recommended instrument settings, see the indi- vidual element analysis pages in "Methods for Chemical Analysis of Water and Wastes." NOTE: The 1974 edition of this manual is currently being revised. This revised edition will be available early in 1979. The use of background correction for furnace analysis to correct for non-specific absorbancs and scattered light is required. Background correction is also required for direct aspiration unless it can be shown to be unnecessary. All furnace analyses shall be conducted using methods of standard additions, while noting the described limitations of its use as given in the revised manual. Also, since method of standard additions may be required for direct aspiration, verification is required to justify its omission. ------- |