T/QAS 007-2019 Brine Lithium Determination by Inductively Coupled Plasma Mass Spectroscopy in Brine Solution

Scope

Main technical content: 1. Principle: After appropriately diluting the sample, it is detected using inductively coupled plasma mass spectrometry (ICP-MS). Elements are identified based on their mass spectra or characteristic ions, and quantified using the internal standard method. The sample is introduced into the atomization system by carrier gas and enters the axial channel of the plasma as an aerosol. There, it is fully evaporated, dissociated, atomized, and ionized at high temperatures and in an inert gas environment. The resulting charged positive ions are collected by the ion collection system and analyzed by the mass spectrometer based on their mass-to-charge ratio (m/z) to determine their elemental identity and concentration. Within a certain concentration range, the signal response value at the element's mass number is proportional to its concentration. 2. Reagents and materials: Unless otherwise specified, only high-purity reagents and water meeting GB/T 6682 standards for analytical laboratories are used in the analysis. a) Nitric acid: ρ(HNO3) = 1.42 g/mL; b) Nitric acid: (5+95); c) Li standard solution (1000μg/mL): commercially available. 3. Instruments and equipment: The main instruments and conditions involved in the experiment are as follows (see Appendix A for unmentioned items): a) Inductively coupled plasma mass spectrometer; b) Analytical balance (resolution 0.1 mg). 4. Sample storage: The samples are stored in sealed plastic buckets. 5. Analysis steps: 5.1 Determination of the sample: After appropriately diluting the sample with (5+95) nitric acid (b), Li is measured using the ICP-MS. It is generally recommended to control the total salt content of the diluted solution to less than 1 g/L. 5.2 Preparation and plotting of standard solutions: Gradually dilute the Li standard solution (c) with (5+95) nitric acid (b) according to Table 1 and perform measurements under the working conditions specified in Appendix

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