Environmental Express HotBlock CURRENT - Manual (Page 27)

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HotBlock™: Operation and Instruction Manual Adaptation of EPA Method 3050B
3.6 Add 1mL DI Water and 1.5mL of 30% H
2
O
2
slowly. Allow an exothermic
reaction to occur. Wait 5-10 minutes and place samples back in the
HotBlock™ with the ribbed watch glasses in place. If effervescence starts
to occur lift the samples out of the HotBlock™ and allow the reaction to
continue. Do not let the samples foam out of the vessel. (Reducing the
HotBlock™ display temperature by 10°C should reduce the effervescence
while maintaining the sample temperature).
3.7 Continue to add 0.5mL of H
2
O
2
(no more than 5mL total) until the sample
remains unchanged in color (no longer than 30 minutes). Continue
heating for a total of 2 hours or until volume has been reduced to
approximately 5mL.
3.8 For the analysis of samples for FLAA or ICP-AES, add 5mL concentrated
HCl to each sample and cover with a ribbed watch glass and reflux at
95°C for 15 minutes. GFAA and ICP-MS digestions, skip this step.
3.9 After cooling, dilute to 50mL with DI Water.
3.10 If necessary, filter with SC0401 (or appropriate FilterMate) to remove
insoluble material.
All QC samples, concentration limitations, elemental lists and reagent
specifications are addressed in depth in EPA Method 3050B. Safety concerns are
also part of the full method. Follow the instructions listed in EPA Method 3050B.
These steps should only be used as a guide to help improve the performance of
your HotBlock™.
1.0 Scope and Application
1.1 The following procedures have been written as an aid to NIOSH Method
7303 for use with the Environmental Express HotBlock™. Method 7303 is
for the preparation of cellulose ester membrane filters commonly used in
air sampling devices. Use EPA Method 7303 for reference while following
the sample preparation steps outlined below. A complete list of elements
appropriate for analysis is included in Method 7303. Analysis can be
performed by ICP or AA.
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
Adaptation of NIOSH Method 7303 for use with the
Environmental Express HotBlock™™ Digestion System
Revised 05.05