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DETECTION OF DIVALENT TRANSITION METAL IONS IN COMPLEX MEDIA BY CAPILLARY ELECTROPHORESIS

A capillary electrophoretic method was developed that analyzes Cu, Ni, Zn, and Au, at concentrations as low as 10 mg/L in nutrient media containing 540 mg/L Na, 270 mg/L K, 50 mg/L Mg, and 27 mg/L Ca. The analysis uses 400uL samples, permitting aliquots to be taken during the course of a shake-flask experiment without introducing volumetric errors. Multiple analyses can be made from the same sample. A sample takes 10 minutes to run, with a 2.5 minute purge and 10-second injection between samples, and is automated, permitting overnight analysis. No special sample preparation was required.

This method is useful for determining rates of metal uptake, optimizing nutritional requirements, microbial growth rates, and the effect of varying environmental factors for metal-sorbing organisms. This method has been applied to research on the copperimmobilizing fungus Penicillium ochro-chloron, supported in part by USEPA Grant #R823341-01-0.

Key words: capillary electrophoresis, transition metals, complex media.