Determination of lithium at ultratrace levels in biological fluids by flame atomic emission spectrometry. Use of first-derivative spectrometry

Abstract

The use of zero-order and first-derivative flame emission spectrometry has been investigated for the determination of basal concentrations of lithium in serum and urine at the µg dm^–3 level. No significant matrix effect was observed; however, it was necessary to make use of background correction techniques. Two or three wavelength measurements and first-derivative spectrometry were used for this purpose; both methods gave similar results. Detection limits for serum of approximately 0.09 µg dm^–3 were found by both zero-order and first-derivative emission measurements, while normal lithium levels were found to be 29.3 and 1.17 µg dm^–3 for urine and serum, respectively.