Improvement of a Microwave Wet Digestion Method for Determination of Elements By ICP-OES in Biological Samples.

Proper sample preparation by microwave digestion for elemental quantification is a necessary and time intensive step in biological tissue testing. Properly digested samples, ready for elemental analyses by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), greatly reduce ICP-OES instrument failures from clogged nebulizers that result from high levels of dissolved solids. Our laboratory was able to refine and optimize biological sample preparation using a newer microwave assisted digestion system, the NOVA Wave from SCP Science, with nitric acid (HNO3) and hydrogen peroxide (H2O2) as extract solvents. Recoveries were assessed against Standard and Certified Reference Materials (SRM/CRM) and by comparison to existing digest methods. The revised method is also compared to a dry ashing sample preparation method with several types of biological samples. Improvement was noted in the standard wet digest method for most elements with these modifications.