Determination of Rare Earth Elements in Seawater by ICP-MS with Magnesium Hydroxide Coprecipitation, Enrichment and Separation

Abstract

In this paper, a method for the determination of 14 rare earth elements in seawater by inductively coupled plasma mass spectrometry was established through optimization of conditions, standard verification, etc. adding NH3·H2O solution directly into seawater to form coprecipitation, enrichment and separation of rare earth elements and magnesium hydroxide. After co-precipitation and centrifugation of seawater samples, the main matrix substances were separated and the target rare earth elements were enriched. The conditions for co-precipitation and enrichment of magnesium hydroxide are as follows: the optimum addition amount of 1 : 1 NH 3 H 2O solution is 0. 35mL, precipitation cleaning times for 1 time, standing time for 5min. Methods The standard addition recovery rate of rare earth elements was 88. 7%-107. 1%, the method blank of rare earth element is 0. 008×10－12-0. 441× 10-12, the lower limit of quantification is 0. 054×10－12-0. 423×10-12 with RSD of 2. 8%-8. 6%. The established method is consistent with the determination results of seawater standard substance NASS-6. The method has the advantages of high accuracy and precision, simple and rapid operation, and can be used for quantitative and accurate determination of rare earth elements in large quantities of seawater samples.