4B - Lithium Metaborate/Tetraborate Fusion - ICP
Samples are prepared and analyzed in a batch system. Each batch contains a method reagent blank, certified reference material and 17% replicates. Samples are mixed with a flux of lithium metaborate and lithium tetraborate and fused in an induction furnace. The molten melt is immediately poured into a solution of 5% nitric acid containing an internal standard, and mixed continuously until completely dissolved (~30 minutes). The samples are run for major oxides and selected trace elements (Code 4B) on a combination simultaneous/sequential Thermo Jarrell-Ash ENVIRO II ICP or a Varian Vista 735 ICP. Calibration is performed using 7 prepared USGS and CANMET certified reference materials. One of the 7 standards is used during the analysis for every group of ten samples.
Totals should be between 98.5% and 101%. If results come out lower, samples are scanned for base metals. Low reported totals may indicate sulphate being present or other elements like Li which won’t normally be scanned for. Samples with low totals however are automatically refused and reanalyzed.
For accurate levels of base metals (Cu, Pb, Zn, Ni and Ag), option 4B1 (see below) is recommended. Option 4B-INAA (see below) is recommended for As, Sb, high W >100 ppm and Cr > 1,000 ppm.
Fusion ICP
Trace Elements
|
Oxide
|
Detection
Limit (%)
|
|
Element
|
Detection
Limit (ppm)
|
|
SiO
2
|
0.01
|
|
Ba
|
2
|
|
Al
2
O
3
|
0.01
|
|
Sr
|
2
|
|
Fe
2
O
3
|
0.01
|
|
Y
|
1
|
|
MgO
|
0.01
|
|
Zr
|
2
|
|
MnO
|
0.001
|
|
Sc
|
1
|
|
CaO
|
0.01
|
|
Be
|
1
|
|
TiO
2
|
0.001
|
|
V
|
5
|
|
Na
2
O
|
0.01
|
|
|
|
|
K
2
O
|
0.01
|
|
|
|
|
P
2
O
5
|
0.01
|
|
|
|
|
Loss on Ignition
|
0.01
|
|
|
|
|