Environmental Express HotBlock CURRENT - Manual (Page 26)

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HotBlock™: Operation and Instruction Manual Adaptation of EPA Method 3050B
1.0 Scope and Application
1.1 The following procedures have been written as an aid to EPA Method
3050B for use with the Environmental Express HotBlock™. EPA Method
3050B is for the preparation of sediment, sludge, and soil samples
for analysis. Use EPA Method 3050B for reference while following the
sample preparation steps outlined below. A complete list of elements
appropriate for analysis is included in EPA Method 3050B. Analysis can
be performed by flame atomic absorption, GF/AA, ICP and ICP-MS.
2.0 Apparatus and Materials
2.1 HotBlock™ for Metals Digestions — Model Numbers SC100, SC150*, or
SC154
2.2 Polypropylene Digestion Vessels — Catalog # SC475 (or SC490 for use
with HotBlock™ SC150)
2.3 Ribbed Watch Glasses, Catalog # SC505 or Reflux Caps, Catalog # SC506
(for use with SC490 vials for HotBlock™ SC150, use Ribbed Watch Glasses,
Catalog # SC610 )
2.4 FilterMate™ — Catalog # SC0401 (or appropriate FilterMate) for sample
filtration if necessary
* Note: When using the SC150 block with the SC490 digestion vials with a 100mL sample,
double the volume of all reagents and acids added.
3.0 Procedure, Sample Preparation
3.1 Mix sample thoroughly to achieve homogeneity and sieve if appropriate.
For each digestion procedure, weigh to the nearest 0.01 gram and
transfer a 0.5-1-gram aliquot (or appropriate amount for your lab) to the
SC475 polypropylene digestion vessel. For best results, weigh the sample
directly in the vessel on a tared balance.
3.2 Add 5mL (1:1) HNO
3
+ DI Water and swirl. Cover with a ribbed watch
glass or reflux cap and heat the sample in the HotBlock™ at 95±5°C for
15 minutes without boiling.
Note: If using the watch glass, adjust the HotBlock™ temperature so that a 50mL, 5% acid
solution is heated to 85°C. Laboratory tests have proven that the addition of the ribbed
watch glass will add approximately 10°C to the sample temperature. Refer to page 7 of
the operations manual for instructions on HotBlock™ temperature adjustment.
3.3 Allow the sample to cool, then add 2.5mL concentrated HNO
3
and reflux
at 95°C for 30 minutes. Repeat this step until NO brown fumes are given
off by the sample.
3.4 Heat sample with the ribbed watch glass to a volume of about 5mL or for
2 hours at 95±5°C . Do not allow the sample to boil or go dry. Neither
of these aspects should occur if the temperature of the HotBlock™ is
adjusted correctly.
3.5 Using the polycarbonate transfer racks, remove samples from the
HotBlock™ and cool completely (it is very important that samples are
cooled completely).
Adaptation of EPA Method 3050B for use with the
Environmental Express HotBlock™™ Digestion System
Revised 05.05