Analysis of Plant Materials for Toxic and Nutritional Elements with the NexION 350 ICP-MS

Plants primarily serve as a food substance, being an important source of nutrients. However, toxic elements can also be found in plants, primarily through uptake from the soil, water, and fertilizer. Therefore, it is important to measure both the nutritional and toxic elemental content of plants and plant materials.

Several challenges arise in the elemental analysis of plants. First, because both toxic and nutritional elements must be measured, a wide dynamic range is required. Plants are complex biological entities which require sample preparation, usually consisting of homogenization followed by digestion in order to break down the complex matrix and extract the elements. Despite these steps, matrix-induced spectral interferences still persist which could cause false readings, especially for the toxic elements. Therefore, Collision or Reaction Cell technology has to be used to remove the interferences.  

One plant species which is gaining considerable interest in the U.S. is cannabis (i.e. marijuana) since its use has been legalized in several states, both for recreational and medicinal purposes through inhalation and consumption in food products. With its increased use, interest in the toxic and mineral element content has also risen.

An additional challenge of cannabis analysis in the U.S. is legally attaining samples, since it is illegal in some states. However, hops are a generally accepted surrogate for cannabis due to its similar chemical and physical properties.

This work discusses the analysis of hops (as a surrogate for cannabis) for both toxic and nutritional elements with ICP-MS.