The determination of lithium in plasma and whole-blood

Lithium is determined in plasma or whole-blood following a twenty-fold dilution with 0.1 N HC1. This would be applicable to monitoring plasma levels in patients receiving lithium carbonate for the treatment of depression. Plasma lithium levels in normal subjects are very low and best determined by electrothermal atomisation. 

Working standard. Dilute stock standard twenty-fold with 0.1 N HC1. 

Dilute the 140meqNa, 5meqKl 1 solution twenty-fold with 

Magnesium, as for calcium, is determined following simple dilution (1 in 50) with lanthanum diluent. Because red blood cells contain high levels of magnesium great care has to be taken to avoid haemolysis of red blood cells. It is convenient to measure both calcium and magnesium on the same sample. 

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