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NYC 9/11 Public Portal Document

FROM : FAX NO. : Jan. 08 2000 10:35PM P19 .Vl. i . 17. .tJrJ1 .0 , L7r I'I JI~t.. G i r y1\1A I IL-1 11 r1L. - --

LAO by Flame AAS Rnesrod 7082, Issue 2 dst d18 Auoustust 1984- Pooe 8 oP 7 or 12 sample vessels. Any vessels containing 6 n1L of nitric ecld for reagent blank purposes are counted as sample vessel$. When fewer t$+sn the recommended number of samples are to be digested, i.e., three sample* plus one bunk the remaining vessels should be filled with 0 mL of nllrfc acid to achieve the full complement of vessels. This provides an energy balance since the microwave power absorbed Is proportional to the total mass in the cavity [141. Irradiate each group of samples to achieve a temperature of 180 °C in fire minutes at a pressure of 60 psi. Continuo to Irradiate to achieve a temperature of 180 'C at 100 psi after 26 minutes. Continue digestion for five minutes, A sample digestion program for 12 samples is presented In the following table,

PROGRAM VARIli„P$ FOR PAiNT CHIPS 6AMPi A. PIG!RTSOP WITH NITRIC ACID

..— _.. (1) (2) ,. (3) Power 90% 90% 0% Pressure, psi 50 100 0 Run Time, min 10;00 2000 05:00 Time t P. mint 05:00 15:00 00:00 Temperature 180'C 180°C 0°C ran speed 100% 100% 100% Number of Vessels: 12 Llgndd Volume per 6 nil,. Vessel: sample Weight: 0.1 g

If the analyst wishes to digest other than two, six, or 12 samples at a time, use different of power as long as they result in the same time and temperature valu$o conditions. e. At the end of the microwave program. etlow the vessels to anal for a minimum of five befote removing them from the mteroweve unit. If a loss of sample Is detected (e.g., minutes overflow oollectlon vessel, 5uId outside liner), determine the reason for the loss (e.g..material In vessel seal integrity, use of a digestion time longer than 30 minutes, too Joss of large improper heating conditions). Cjftce the source of the Ives has been corrected, a sample, or sample beginning at 8pdioln 2. If insuiTicilnt material (s available for reanalysis, dilute new prepare a remaining dipastste and note that some sampie toes may have occurred. t. Uncap and vent each vessel In •tome hood, Add 20 mL reagent water, and shake to mix thoroughly. TrenMsr the erarraple to en ®dd.cleaned then reseal vassals digested sample oentalrts psrtJouIetes which, may dog reebulleers polyethylene bottle. if the the sample into the Instrument„ show the sample to scale Cr After or it: interfere with infection of

settling. Allow the sample to stand until the supernatant is does not doer, filter the sample. clear (usually, overnight is sufficient). if it

Filtering: The filtering apparatus must be the sample through quantitative filter paperthoroughly prodesned end rinsed with dilute nitrto avid. Filter inro a second acid-deened container. The digestete is now ready for analysis rbr elements of interest Using the appropriate method.

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