ALS offers the lowest detection levels available in the industry from our super-trace aqua regia and four-acid digestions. These methods are ideal for soil and sediment samples where well-characterised background values will improve anomaly identification. Super-trace detection levels can also be valuable with regional drilling samples where subtle changes in geochemistry can provide information used for large scale fluid flow models and other interpretations.
ALS achieves super trace detection levels using a combination of ICP-AES and ICP-MS determinations on the same sample. The two sets of data are combined to provide optimal detection and ranges for 50+ elements.
ALS offers both a standard and variation of an aqua regia digestion from a 0.5g sample. Method ME-MS41L™ method utilises the typical aqua regia acid mixture of nitric and hydrochloric acids in a 1:3 ratio. A weaker digestion using a 1:1 ratio of nitric and hydrochloric acids is also an option with method ME-MS41W™. Both methods use relatively low temperatures for digestion to maintain volatiles such as Hg in the sample. Gold reported by these methods is usually considered as semi-quantitative as the sample weight is too low to be representative.
Code | Analytes & Ranges (ppm) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
ME-MS41L™* 0.5g sample | Ag | 0.001-100 | Co | 0.001-10,000 | La | 0.002-10,000 | Pt | 0.002-25 | Th | 0.002-10,000 |
Al | 0.01%-25% | Cr | 0.01-10,000 | Li | 0.1-10,000 | Rb | 0.005-10,000 | Ti | 0.001%-10% | |
As | 0.01-10,000 | Cs | 0.005-500 | Mg | 0.01%-25% | Re | 0.0002-50 | Tl | 0.001-10,000 | |
Au | 0.0002-25 | Cu | 0.01-10,000 | Mn | 0.1-50,000 | S | 0.01%-10% | U | 0.005-10,000 | |
B | 10-10,000 | Fe | 0.001%-50% | Mo | 0.01-10,000 | Sb | 0.005-10,000 | V | 0.1-10,000 | |
Ba | 0.5-10,000 | Ga | 0.004-10,000 | Na | 0.001%-10% | Sc | 0.005-10,000 | W | 0.001-10,000 | |
Be | 0.01-1000 | Ge | 0.005-500 | Nb | 0.002-500 | Se | 0.003-1000 | Y | 0.003-500 | |
Bi | 0.0005-10,000 | Hf | 0.002-500 | Ni | 0.04-10,000 | Sn | 0.01-500 | Zn | 0.1-10,000 | |
Ca | 0.01%-25% | Hg | 0.004-10,000 | P | 0.001%-1% | Sr | 0.01-10,000 | Zr | 0.01-500 | |
Cd | 0.001-1000 | In | 0.005-500 | Pb | 0.005-10,000 | Ta | 0.005-500 | |||
Ce | 0.003-500 | K | 0.01%-10% | Pd | 0.001-25 | Te | 0.003-500 |
*Gold determinations by this method are semi-quantitative due to the small sample weight used. A weak aqua regia (1:1 ratio HCl:HNO3) digestion is also available, use code ME-MS41W™. For Au with multi-element using a 25g or 50g charge please use AuME-ST43™ or AuME-ST44™.
The rare earth elements (REEs) and lead isotope concentrations add new dimensions to super trace data. REEs may still be useful pathfinders despite reflecting only the labile (aqua regia extractable) component, while Pb isotopic signatures can be used in fingerprinting and hydrothermal fluid history.
Methods can be added onto the ME-MS41L™ or ME-MS41W™ analysis to provide Pb isotopes and/or rare earth element concentrations: MS41L-PbIS™ and MS14L-REE™ (or W variation). These analyses can add new dimensions to super trace data.
Code | Analytes & Ranges (ppm) | |||||
---|---|---|---|---|---|---|
MS41L-REE™ | Dy | 0.002-1000 | Ho | 0.001-1000 | Sm | 0.002-1000 |
Er | 0.002-1000 | Lu | 0.001-1000 | Tb | 0.001-1000 | |
Eu | 0.002-1000 | Nd | 0.002-1000 | Tm | 0.001-1000 | |
Gd | 0.002-1000 | Pr | 0.002-1000 | Yb | 0.002-1000 | |
MS41L-PbIS™ | ²⁰⁴Pb | 0.005-10000 | ²⁰⁶Pb | 0.005-10000 | ²⁰⁷Pb | 0.005-10000 |
²⁰⁸Pb | 0.005-10000 |
When deciding upon a multi-element package, the choice is often between a four-acid or aqua regia digestion. Each method has its advantages and ideal uses that need to be considered against drawbacks. In general, aqua regia is a partial digestion therefore analyses only represent the portion of the sample extracted. Four-acid digests a larger portion of the sample producing a “near-total” analysis for many mineral types and analytes.
Aqua regia digestions using 25g or 50g sample aliquots allows gold to be reported quantitatively .
MORE INFORMATIONFor the analysis of more advanced projects, detection levels higher than the super trace methods may be applicable.
MORE INFORMATION