Direct REE determination in fresh waters using ultrasonic nebulization ICP-MS

An ultrasonic nebulization inductively coupled plasma MS method was used to determine very low concentrations of rare earth elements (REE) in 15 samples of spring water from northern Israel. Matrix effects due to relatively high contents of total dissolved salts were overcome by using rhenium as an internal standard. Concentrations of light REE ranged from 0.02 to 13 ng per litre and those of heavy REE from 0.01 to 3 ng per litre. Limits of detection were in the range 0.005 to 0.05 ng per litre. Recoveries from samples spiked with REE varied from 85 to 120 per cent for a 1 ng per litre spike and from 97 to 107 per cent for a 10 ng per litre spike. Without the internal standard, recoveries were 60 to 85 per cent. The method was validated by the analysis of SRM SLRS-3 riverine water. In addition, data for 2 selected springs were normalized to North American Shale Composite to characterize the REE patterns. Water from the Dan spring gave a typical sedimentary carbonate pattern, whereas water from the Shamir spring gave a pattern found in basaltic rocks of the Golan Heights.