NIOSH 7601
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This is the revised format of method NIOSH
P&CAM 106. This method is an elemental analysis; silicon is analyzed and reported out
as silicon dioxide (SiO2). Can analyze individually quartz or cristobalite or
tridymite, but cannot distinguish the different polymorphs of silica. Calls for use of
NIST-traceable Standard Reference Material (SRM) or Min-U-Sil 5 (Pennsylvania Glass Sand
Co., Berkley Springs, WV). Technique requires great skill to remove all silicon-containing
interferences (such as silicates) without significant loss of crystalline silica.
Silicates can be removed using a phosphoric acid cleanup procedure. Silicon carbide and
many silicate interferences cannot be removed by the acid treatment. |