Comparison of flame atomic-absorption techniques for the determination of copper and zinc in fractionated blood plasma

Abstract

The sensitivity, detection limit, reproducibility and matrix effects of five flame-based atomic-absorption methods, used for the determination of copper and zinc in plasma protein fractions that had been separated by ion-exchange column chromatography, were measured. The methods were continuous nebulisation, pulse nebulisation, pulse nebulisation into a slotted quartz tube and atomisation from a Delves cup and from a molybdenum wire loop. It was found that while atomisation from a solid support produced a considerable improvement in absolute sensitivity (measured in pg per 0.0044 peak-height absorbance), the concentration sensitivity (measured in ng ml^–1 per 0.0044 absorbance) was not appreciably improved except for the more volatile elements. Only modest improvements were achieved using the slotted quartz tube and again the more volatile elements produced the greatest enhancement. It was concluded that of the methods examined, pulse nebulisation was the preferred technique.