Fast and Reliable Determination of Alkali and Alkaline-earth Elements in Biological Fluids Using Laser-induced Breakdown Spectroscopy

Abstract

This work is focused on the development of a quantitative assay for the determination of Na, K, Ca, Mg, and Li in blood serum, urine, and saliva by a simple procedure using single pulse laser-induced breakdown spectroscopy (LIBS). All analyses were performed on samples in the form of homogeneous glass-supported polyacrylamide gel films containing Rb and Ba as internal standards. No additional sample preparation was necessary with only 20 μ L of sample consumption. Limits of detection achieved for Li, Na, K, Ca, and Mg with the proposed setup were 0.2, 6.2, 0.6, 1.9, and 1.7 ppm, respectively. The resulting linearity for the five elements ranged from 3 times below to 2 times above the expected concentration levels variation. Relative standard deviations lower than 10% indicate the excellent precision. The trueness was proved by spike experiments and by comparing the LIBS results to an automated clinical laboratory assay.