Determination of rare earth elements by inductively coupled plasma mass spectrometry with introduction of organic phase using, ultrasonic nebulizer

Analytical method to determine rare earth elements which were extracted to organic phase by inductively coupled plasma mass spectrometry(ICP-MS) was investigated. Organic phase which had extracted rare earth elements was directly aspirated into ICP-MS by ultrasonic nebulizer(USN) in order to reduce solvent load to the plasma. Then, the count rate increased when MIBK(methyl isobutyl ketone) was added to EtOH(ethanol) but decreased when 0.03 M HEH(2-ethylhexyl-2ethylhexyl phosphonic acid, P507, PC88A) was added to solvent which mixed MIBK with EtOH. The optimal temperatures of desolvation system were -10.deg.C for the condenser and 150.deg.C for the heating tube. The optimal nebulizer flow rate which gave maximum count rate and minimum reflect power was 0.7L/min. The optimal pH and extraction time were 4.3 and 10 min for MiBk-0.03 M HEH system. Detection limits which were obtained through calibration curves at the range of 0.2∼20 ng/mL were 0.02∼0.05ng/mL under the optimal experimental conditions