An environmentally compatible and less costly (greener) microwave digestion method of bone samples using dilute nitric acid for analysis by icp-ms

Authors: Bussan, Derek; NIELSEN, FORREST - Retired ARS Employee; DOUVRIS, CHRIS - New York Institute Of Technology; KELZENBERG, BRETT - University Of North Dakota; GRIMESTAD, ALLISON - University Of North Dakota; Cao, Jay

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2024
Publication Date: 11/22/2024
Citation: Bussan, D.D., Nielsen, F., Douvris, C., Kelzenberg, B., Grimestad, A., Cao, J.J. 2024. An environmentally compatible and less costly (greener) microwave digestion method of bone samples using dilute nitric acid for analysis by icp-ms. Biological Trace Element Research. 29(23): Article 5517. https://doi.org/10.3390/molecules29235517.
DOI: https://doi.org/10.3390/molecules29235517

Interpretive Summary: Title: Greener and Safer Method Developed for Preparing Bone Samples for Trace Element AnalysisSummary:Problem: Traditional methods for preparing bone samples for trace element analysis using inductively coupled plasma mass spectrometry (ICP-MS) involve the use of concentrated nitric acid, which poses environmental and safety risks.Accomplishment: Researchers have developed a new, greener, and safer method for digesting bone samples using dilute nitric acid and a microwave-assisted digestion system. This method uses a mixture of 1 mL concentrated nitric acid and 4 mL deionized water, which produces comparable results to the conventional method that employs only concentrated nitric acid.Contribution: The new method reduces the environmental impact and safety risks associated with the use of concentrated acids while maintaining the accuracy and reliability of the analysis. The researchers validated the accuracy of the new method using a certified reference material (NIST 1486 Bone Meal) and found that the recoveries of eight certified elements were within ± 15% of the known concentrations. Statistical analysis revealed no significant differences between the new green method and the conventional method for most elements. The new method also scored 87 on the analytical Eco-Scale, categorizing it as an "excellent green analysis" method.This research highlights the potential for adopting greener and safer practices in trace element analysis without compromising the quality of the results. The implications of this study may extend beyond the analysis of bone samples to other sample matrices, promoting more sustainable and environmentally friendly practices in analytical laboratories.

Technical Abstract: An environmentally compatible and less costly (green) analytical method for the digestion of bone meal samples using microwave-assisted dilute nitric acid (HNO3) was developed and optimized. The method employing a mixture of 1 mL concentrated HNO3 and 4 mL of deionized water gave a comparable performance to the conventional method using 5 mL of concentrated HNO3. Accuracy of the method was validated by using certified reference material NIST 1486 (Bone Meal); percent recoveries were within ± 15% for all eight certified elements. Statistical analysis revealed no significant differences (p > 0.05) in percent recoveries between the green and conventional methods for all elements except calcium. The greenness of the developed method was evaluated by using the analytical Eco-Scale, achieving a score of 87, categorizing it as an "excellent green analysis" method. This research highlights the potential for adopting greener practices in trace element analysis that reduce environmental impact and safety risks associated with concentrated acids.