Dynamic reaction cell inductively couple plasma-mass spectrometry optimization for seawater analysis

摘要

AbstractA direct method for dynamic reaction cell inductively coupled plasma- mass spectrometry (DRC-ICP-MS) trace mineral elements determination in seawater was optimized by Experimental Statistical Design. Five instrumental parameters, such as radiofrequency, sample, nebulizer and reaction gas flows, rejection parameter q and axial field voltage were studied. A Plackett-Burman design was used for screening the most important parameters and the most significant ones were optimized with a Central composite design. Fifteen elements and different isotopes for some of these were considered through the study. The optimization was achieved by using three different reaction gases (NH3, CH4and O2). The optimized method was used for the quantification of trace minerals in a certified seawater sample. The standard mode was adequate for the quantification of those elements that have a reduced number of interferences like111Cd and238U. However, the best results were obtained employing ICP-MS in NH3-DRC mode which allowed the simultaneous determination of elements like51V,55Mn,58Ni,68Zn and238U, which can be determined in the reference sample with an accuracy error lower than 10% and95Mo determined with an accuracy error of 15%. The use of CH4-DRC was restricted to quantify111Cd with an error of 16%. The use of O