Development of an automatic pH-adjustment system for solid phase extraction prior to the determination of REEs in seawater by ICP-MS

摘要: An automatic pH adjustment instrument was developed for solid phase extraction (SPE) of rare earth elements (REEs) using chelating resins. The automation carried out by a spectrometer, an input/output (I/O) board, automatic-switching valve, and personal computer with LabVIEW® programming platform. Contactless monitoring the measuring intensity transmitted light at 550 nm that passed through sample solution added pH-indicator, i.e. methyl red. A reagent adjusting pH, aqueous ammonia solution, sprayed into nebuliser, which permitted addition small amount precise pH. value monitored while open-time valve to add automatically controlled simultaneously measurement light. precision tested confirmed seawater sample. blank values detection limits REEs were given as analytical figures merits. usefulness present method analysing samples from Nikkawa Beach, Kashima Bay, Ishigaki Island. results in these discussed shale normalised REE distribution pattern.