Analytical methodology and elemental selections are crucial to the success of any exploration program. Appropriate methodology selection is important and careful consideration should be given to the dissolution strengths and limitations of the selected technique to ensure that all requirements are covered.
A range of analytical methodology has been developed to handle various exploration applications. The digests offered include aqua regia, four acid, three acid and perchloric acid digestions, utilising ICP-OES, ICP-MS and AAS instrumentation. We can offer either multi-element packages or individual elemental combinations depending on your analytical requirements.
Aqua regia is commonly used for exploration geochemistry and is a mixture of nitric and hydrochloric acids. Aqua regia can digest many different mineral types including most oxide, sulphide and carbonate minerals but will not totally digest refractory or silicate minerals. Although the refractory elements may not be totally digested they have been included because they may be useful for profiling purposes.
MinAnalytical offers three options for the aqua regia digest.
The mini aqua regia for cost effective scanning of large multi-element suites. Ideal for base metal analysis however, precious metals are not available by this method due to the low sample charge weight.
Where Gold and precious metals are required we recommend the 10 or 25 gram aqua regia digest with the same range of cost effective multi element packages.
Aqua regia is a valuable tool for exploration applications but should not be used for resource estimations.
* Please note that Hg may report low due to consequential losses during sample preparation and analysis.
A range of individual elemental options are available for selection. This option may be useful for customising your own elemental suite or when only select elements are required.
The four acid digestion is a mixture of hydrofluoric, nitric, perchloric and hydrochloric acids. This digest is suitable for dissolving silica based samples and approaches total dissolution for most minerals. However, some highly resistant refractory minerals may not be totally digested and may require a fusion to ensure complete dissolution. The heavy rare earth elements may not be totally digested by this method. Four acid digestions may volatilise some elements.
A range of elements and packages are available. These options include ICP-OES and ICP-OES/MS instrument combinations.
The three acid digestion is a mixture of nitric, perchloric and hydrochloric acids. Most sulphides, oxides and carbonates will digest by this method. However, refractory minerals and most silicates may only be partially digested. Dissolution is dependent on the element and mineral type. This digest is not recommended for lithophile elements.
The perchloric acid digestion is a high temperature digest with the final leach taken up in hydrochloric acid. The digest will dissolve most base metal sulphides and oxides and is only suitable for base-metal exploration screening applications. Refractory and silicate minerals may only be partially digested.