Paper Title
Effect of HF Addition on Microwave-Assisted Acid-Digestion for the Determination of Calcium

Abstract
This study assessed the concentrations of calcium in different geological samples using inductively coupled plasma mass spectrometry (ICP-MS). The samples were prepared using a wet microwave digestion system and three combined acid mixtures. The research proved that adding hydrofluoric acid (HF) to samples leads to the deposition of calcium, which may produce inaccurate results. In addition, the results indicated that as the concentration of the HF increased, the calcium concentration decreased as a result of CaF2 formation and precipitation. Keywords - HF, ICP-MS, Acid-Digestion, Microwave Digestion