How to analyse gold in plant tissue?

The accumulation of trace elements in plants has many interesting applications. For example, the analysis of plant tissue for zinc, lead, arsenic and mercury, is a suitable method for monitoring atmospheric release of these contaminants from industrial sources. Anomalous concentrations of heavy elements, such as cadmium, can be found in plant species that grow in close proximity to metal smelters. Some plants can naturally accumulate high concentrations of trace elements. For example, Hybanthus Floribundus is well-known for its ability to accumulate more that 0.1% of nickel (Ni), a concentration that is toxic for other plant species. Plants’ trace elements levels are also used in mineral prospecting. Mineral exploration companies collect plant tissue, and analyse it for precious elements, such as gold. Recent developments in analytical instrumentation, such as ICP-MS (inductively coupled plasma mass spectrometer), allow detection of very low concentrations of gold in the range of parts per billion (microgram/kilogram). There are various methods of sample preparation and analysis of plant tissue for gold. Typically, the analysis includes dissolution of a dry or ashed material in a mixture of hydrochloric and nitric acids (aqua regia), followed by analysis using ICP-MS. Another method uses neutron activation analysis. This requires a small amount of powdered dry plant tissue, that is compressed into a small disc and irradiated with gamma-rays. Our Biogeochemical Eucalyptus Leaf reference material is able to assist with any quality analyses and control queries that you may have.