Introduction:

a black precipitate was observed in the filter during the infusion of a parenteral nutrition without lipids. There are similar findings published in which copper and sulphur (from cysteine) were found in the composition of the precipitate.

Objective:

to determine if copper and cysteine are involved in the formation of the precipitate.

Methods:

samples of the parenteral nutrition solution were taken before and after its passage through the filter. Amino acids concentrations were analysed in both samples by ion exchange chromatography and post-column derivatization with ninhydrin in a Biochrom 30 device. Copper concentrations were measured by atomic absorption spectrometry in a PerkinElmer AAnalyst(tm) 200 device.

Results:

a decrease in cysteine concentration of 29.3% was found. The concentration of copper decreased by 75.9%.

Conclusions:

the decrease in the concentrations of cysteine and copper in the filtered solution suggest that both are involved in the formation of the black precipitate observed in the filter.

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