QUANTITATIVE ESTIMATION OF LITHIUM

The wide applicability of lithium-based materials in the field of electronic industries especially for the rechargeable batteries is one of the upcoming technologies in today’s trend. Since lithium is known as quite toxic and prone to contamination, therefore, quantitative estimation of this material using highly precise instruments like the AAS (in emission mode) or the ICP-AES is always useful. Recently, there was an attempt to carry out quantitatively analysis of lithium in its pure inorganic compounds like lithium tetraborate (Li2B4O7) and lithium metaborate (LiBO2) using our ICP-AES. The samples were digested in 1:5 HNO3 medium at a very low heat for 5-10 minutes. The calibration curves at the respective wavelengths of Li (670.784 and 610.362 nm) were made using the CRM standards of concentrations 10 and 100 mg/L. Figure 1 shows the calibration curves at the above wavelengths whereas, Fig.2 shows the corresponding emission spectra of samples along with the standard materials at those corresponding wavelengths. However, the highest retention of lithium was obtained at the wavelength of 670.784 nm as compared to 610.362 nm due to a better sensitivity of the former wavelength as compared to the later. Table 1 shows in detail the results of the experiment carried out in this connection. The established method will be able to analyze lithium content in other commercial lithium based inorganic material in future.

Fig. 1 Calibration curves made using lithium liquid CRM standards of 10 and 100 mg/L at the wavelength of 670.784 nm and 610.362 nm.

 

Fig. 2 Spectral comparison of the emission spectra of lithium at the wavelengths of 670.784 nm and 610.362 nm for the standards and samples.

Table 1: Quantitative estimation of lithium in lithium tetraborate and metaborate carried out in ICP-AES at different wavelength

Note: Repeatability was tested at wavelength 670.784 nm and the Li% was found between 7.95 to 8.11 having mean value 8.02.

Contributed by : Mrs. Saswati Ghosh