By Juan Araneda
Lithium is used in many industrial manufacturing processes such as glass, ceramics, lubricating grease, and pharmaceuticals. However, its importance in the last two decades has increased due in part to the superior performance of lithium-ion batteries, which are widely used in a variety of electronic devices, such as notebooks, cellphones, cameras, etc. Lithium is mainly sourced from either spodumene or brine and its quantification is crucial in every step of its the extraction and production. The most common techniques for lithium quantification are atomic absorption (AA) and inductively coupled plasma (ICP) spectroscopy. However, both methods require significant sample manipulation and are prone to interference caused by other ions present in solution.
Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most powerful techniques available to chemists, but it is not as widely used in industry as other techniques such as UV-Vis, ICP, AA and IR spectroscopy due to the cost and size associated with traditional high-field instruments. However, the emergence of benchtop NMR spectrometers that are affordable, portable, and require minimal maintenance has accelerated the introduction of this technique in industrial settings. We have developed a new method to determine the lithium content in real brine samples using benchtop NMR instruments without any additional sample preparation, dilution, or need for deuterated solvents. The method was validated, and limits of detection and quantification of 40 and 100 ppm, respectively, were established. Linearity, precision, and bias were also experimentally determined, and the results will be presented in this poster.