Environmental Express HotBlock CURRENT - Manual (Page 21)

800.745.8218 / 843.576.1147 / www.environmentalexpress.com Environmental Express • 19
HotBlock™: Operation and Instruction Manual EPA Method 200.8
1.0 Scope and Application
1.1 The following procedures have been written as an aid to EPA digestion
procedure 200.8 for use with the Environmental Express HotBlock™.
EPA Method 200.8 is for the determination of total recoverable analytes
in groundwater, surface water, drinking water, wastewater, and (with
the exception of silica) in solid samples such as sediment, sludge
and soil. Use EPA Method 200.8 for reference while following the
sample preparation steps outlined below. A complete list of elements
appropriate for analysis is included in EPA Method 200.8. Analysis can be
performed by 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: For all procedures, 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, Aqueous Sample Preparation -- Dissolved Analytes
(EPA Method 200.8, Paragraph 11.1)
3.1 For the determination of dissolved analytes in ground and surface
waters, pipet a 20mL or greater aliquot of filtered, acid-preserved sample
into the SC475 digestion vessel.
3.2 Add an appropriate volume of (1+1) HNO
3
to adjust the acid
concentration of the aliquot to approximate a 1% (v/v) nitric acid
solution. If the direct addition procedure is being used, add internal
standards, cap and mix.
Note: If a precipitate is formed during acidification, transport or storage the sample
aliquot must be treated using procedures for Total Recoverable Analytes.
4.0 Procedure, Aqueous Sample Preparation — Total Recoverable Analytes
(EPA Method 200.8, Paragraph 11.2)
Note: This section applies to water samples containing turbidity of greater than 1 NTU.
4.1 For each digestion procedure, transfer 50mL of well-mixed, unfiltered,
acid-preserved sample into the SC475 polypropylene vessel.
4.2 Add 1.0mL (1+1) HNO
3
and 0.5mL of (1+1) HCl and swirl. Heat in
the HotBlock™ at a sample temperature of 85°C. The HotBlock™ set
temperature should be approximately 105°C. The temperature of a
reference blank should be tested to ensure correct temperature.
Adaptation for EPA Method 200.8, for use with the
Environmental Express HotBlock™ Digestion System
Revised 05.05