The application of resonance monochromators to the determination of lithium in blood serum by atomic absorption spectrophotometry

Lithium in blood serum can be determined rapidly and with sufficient accuracy by atomic absorption measurement of solutions of blood serum diluted with water, using either a conventional atomic absorption spectrophotometer or one with a resonance monochromator. Calibrating solutions contain sodium and potassium at approximately the concentrations present in the serum solutions as these metals cause a slight enhancement of lithium absorption in the air/coal gas flame. Results are reproducible to within ±0.2 μg Li/ml in the serum and the limits of sensitivity attainable for samples diluted 1:10 are 0.3μg Li/ml in the serum with the conventional instrument and 0.6 μg Li/ml in the serum with the resonance monochromator.