Stability and behaviour of selenium in total parenteral nutrition solutions

Selenium stability in amino acid/dextrose/electrolytes/ascorbic acid/trace elements was evaluated by a specific and sensitive fluorimetric method of selenium(IV) determination. Ascorbic acid particularly with copper(II) ions, reduced selenium(IV) in selenium metal (Se). Cysteine present in amino acids solution induces complexation with selenium. The complex has been identified by high-performance liquid chromatography when cysteine and selenite are mixed in 4 1 molar ratio. The complex is releasing cystine and selenium(II). These reactions are responsible for the complete loss of selenium(IV) in total parenteral nutrition solutions.