Environmental Express HotBlock CURRENT - Manual (Page 28)

800.745.8218 / 843.576.1147 / www.environmentalexpress.com Environmental Express • 26
HotBlock™: Operation and Instruction Manual NIOSH Method 7303
* 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, Filter Preparation
3.1 Remove filter from cassette holder and fold into quarters taking care not
to lose any sample.
3.2 Place in SC475 digestion vessel and add 1.25mL HCl.
3.3 Cover with plastic watch glass or reflux cap. Place in HotBlock™ and heat
at a sample temperature of 95°C for 15 minutes.
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.
3.4 Remove samples from the HotBlock™ and cool for 5 minutes.
3.5 Remove watch glass and add 1.25mL HNO
3
. Replace watch glass and
return to HotBlock™ at sample temperature of 95°C for 15 minutes.
3.6 Remove the sample from the HotBlock™ and cool for at least 5 minutes.
Rinse watch glass into vessel. Discard watch glass.
3.7 Dilute to 25mL final volume with distilled, deionized type II water.
All QC samples, concentration limitations, elemental lists and reagent specifications
are addressed in depth in Method 7303. Safety concerns are also part of the full
method. Follow the instructions listed in Method 7303. These steps should only be
used as a guide to help improve the performance of your HotBlock™.
Methodology Note:
The following procedure has been written as an aid for use with the Environmental
Express HotBlock™™ and strictly follows HUD (Housing and Urban Development)
guidelines for Lead in Dust Wipes Appendix A-5.0 which references NIOSH 7082.
1.0 Scope and Application
1.1 This application deals with the preparation of samples using lead wipes,
specifically the GhostWipe from Environmental Express. The sample is
heated in the presence of Nitric and Hydrochloric acids to dissolve the
wipe and all lead compounds into solution. Analysis can be performed
by flame atomic absorption (FLAA) or inductively coupled plasma
technique (ICP).
2.0 Apparatus and Materials
2.1 HotBlock™ for Metals Digestions — Model Numbers SC100, SC150*, or
SC154
Sample Preparation for Lead Analysis with the GhostWipe
Revised 05.05