Rapid determination of lithium in human serum and urine, at physiological concentrations, by inductively coupled argon plasma atomic emission spectrometry

A method is proposed for measuring lithium in serum and urine by inductively coupled argon plasma atomic emission spectrometry. Different mineral elements encountered in these biological fluids do not interfere with the results. The detection limit was 0.017 μ moll−1 in serum and 0.03 μ mol l−1 in urine. Values for within-run relative standard deviations were <2% at lithium concentrations ≥1 μmol l−1 and <3.5% at 0.14 and 0.21 μmol l−1. Thus, it was possible to determine lithium concentration in normal human serum (men = 0.09 μmol l−1; women = 0.15 μmol l−1) and urine (men = 2.32 μmol/24 h; women = 2.78 μmol/24h) the differences between men and women being not significant using Mann and Whitney U-test.