The Estimation of Lithium in Serum

Effect of Short-term and Long-term Lithium Treatment on Uptake and Retention of 10dine-131 in Rat Thyroid

“…Lithium administration in the diet continued until the uptake studies were completed. Blood samples were collected from rats under light ether anaesthesia by occulat vein puncture before and after the uptake studies, and serum was separated by centrifugation for the estimation of lithium levels using an EEL flame photometer, mark II (Brown and Legg 1970).…”

Simple Flame Spectrophotometric Assay of Serum Lithium

“…It seems probable that the freedom from protein interference in the proposed new method, which is in contrast to the findings of Brown and Legg (1970), is a consequence of the narrow spectral band passed by the diffraction grating monochromator used in this method (1.35 nm according to the manufacturers) compared with that afforded by the silica prism used by these authors (approximately 15 nm by extrapolation from manufacturer's data), and the findings of the present work are explicable in terms of almost complete exclusion of the acetyleneprotein spectral continuum by the former but not by the latter. The finding of an increase in nonspecific emission on increasing the slit-width from 0.5 to 2.0 mm is consistent with this view.…”

“…This feature of lithium emission permits the use of an effectively large radiant source to illuminate a relatively small detector, and is no doubt the basis of the high sensitivity found in this work. Thus, a 1/50 dilution of serum provided ample sensitivity for measurement by the new method in contrast to the 1/5 dilution required for the procedure of Brown and Legg (1970). (However, as these authors pointed out, the latter procedure suffered from the reduction of emission due to trichloroacetic acid.…”

“…The accurate determination of lithium in blood serum may be accomplished by procedures involving either flame emission or atomic absorption spectrophotometry (see Brown and Legg, 1970). Jt is apparent that the former technique is preferable since both calculated (Winefordner et al, 1970) and observed (Pickett and Koirtyohann, 1968) values of detection limits show that, for this element, flame emission is more sensitive than atomic absorption spectrophotometry by at least an order of magnitude.…”

“…Prior precipitation of serum protein was found by Brown and Legg (1970) to be necessary in order to reduce non-specific emission to an acceptable level when using instruments having either an optical filter or a silica prism monochromator. Since the spectral band-widths selected by either method are relatively broad (see for example Buell, 1969) in the spectral region concerned (670.8 nm), it seemed possible that the non-specific emission was that of the continuum of the acetylene flame which is known to be increased by protein (Burriel-Marti and RamirezMunoz, 1957).…”