Analytical Suite Metadata

Chemex (lake and stream sediment) FA-NA (Au) + Wt -Au (variable d.l.= 1  for 10g sample or 2 ppm for 5g sample)



Chemex, lake and stream sediment; fire assay pre-concentration, neutron-activation / gamma ray spectroscopy (gold) + weight -Gold has variable detection limit. d.l.= 1ppb for 10g samples or 2 ppb for 5g samples

General Methodology:

Gold was usually determined on a 10 g sediment sample; depending on the amount of sample available, lesser weights were sometimes used.  This resulted in a variable detection limit: 2 ppb for a 5 g sample, 1 ppb for a 10 g sample... The sample was fused to produce a lead button, collecting any gold in the sample, which was cupelled in a muffle furnace to produce a silver (dore) bead.  The silver beads were irradiated in a neutron flux for one hour, cooled for four hours, and counted by gamma ray spectrometry.  Calibration was carried out using standard and blank beads.

Instrument: unstated

Sample material: solid

Sample weight: unstated


Analytical Technique:

Hierarchical classification

Technique >> Radiochemical methods >> Activation analysis >> Neutron activation >> INAA >> DGNAA >> FA-NA

Children

None


Analytical Decomposition:

Hierarchical classification

Decomposition >> Fusion >> Fire Assay

Children

Pb | PbO/Ag | NiS


Analytical Methods:

IndexMethod OrderMethod IDQuantityDetection Limit
1  1024     Au  1
2  1274     Wt 

Associated Analytical Packages:

IndexPackage IDPackage Name
1  310     Chemex (NGR BC stream sediment and moss mat samples, 1988)
2  399     Chemex (NGR lake or stream sediment) fire assay (Au) and weight
Date modified: