Comparative Analysis of Coprecipitation and Solid Phase Extraction for Trace Element Determination in Seawater Samples by ICP-MS

Abstract

Determining trace elements in seawater is important for monitoring the marine environment, and inductively coupled plasma mass spectrometry (ICP-MS) is a widely used technique for this purpose. However, interference problems associated with the sample matrix and low analyte concentrations necessitate sample preparation steps. This study aimed to compare solid-phase extraction (SPE) using Chelex-100 resin with coprecipitation using triethylamine as a method for preparing seawater samples determining As, Cd, Cu, and Pb by ICP-MS. The effectiveness of removing the saline matrix after sample preparation was evaluated by measuring residual chloride, with approximately 96% of this ion being eliminated for both procedures. Despite this, the residual ion concentration led to matrix effects during analyte determination, necessitating calibration by analyte addition for both methods. The pre-concentration efficiency of the elements was assessed by comparing the actual pre-concentration factor with the theoretical factor. For all elements except Cu, coprecipitation achieved pre-concentration values close to the theoretical values. In contrast, with SPE, only Cd and Pb showed values close to the theoretical factor. Considering the sample volume, reagents, and time required, coprecipitation with triethylamine proved to be an efficient alternative to solid-phase extraction for seawater sample preparation.