Microwave Digestion of Brood XIV Periodical Cicadas

Indianapolis, IN

Periodical cicadas, native to Eastern North America, are one of many different varieties of cicadas. Periodical cicadas are distinguished from other (annual) cicadas by their distinct 13- or 17-year emergence pattern. Because these organisms spend the majority of their lifetime underground subsisting on the sap from tree roots and travel only short distances upon emergence, they are promising bioindicators of soil chemistry for a localized geographic area. Although cicadas are promising bioindicators, sample preparation methods are complicated due to the presence of significant quantities of chitin in the exoskeleton. Previous hotplate digestion methods using strong acids and hydrogen peroxide were largely unsuccessful, so microwave digestion methods were investigated in this work. A variety of digestion parameters (temperature, power, time, reagent concentrations) were explored to generate a method capable of successfully dissolving intact periodical cicadas. The optimal digestion method was subsequently used to prepare cicada samples for trace-metal analysis by Inductively Coupled Plasma-Atomic Emission Spectrometry.