Comparison of Different Cleaning Procedures of Root Material for Analysis of Trace Elements

Abstract

When plant roots are analyzed for trace elements, the cleaning procedure used can affect the analytical accuracy in two ways. First, with inadequate cleaning of the root surface, high levels of trace elements in the soil can contaminate the roots. Second, elements present in the root can be leached into the wash solution. In this study, nine different cleaning solutions were tested on Typha latiofolia (common cattail) for both of these effects. The results of this investigation suggested that there is no universal washing procedure for plant root samples. The best procedure was found to be soaking the root three hours in a solution containing 1% detergent (Alconox) made up in deionized water followed by rinsing five times with deionized water. Other reagents (deionized water, 1% detergent with 1 M MgCl₂, 0.1 M HCl, 0.01 M EDTA, 1 M MgCl₂ alone, 1 M NaOAc/HAc) and procedures (ultrasonification) were either less effective at cleaning the surface or leached trace elements from the root itself. On balance, any of the following three washing reagents were acceptable: 1% Alconox, 0.01 M EDTA or 1 M MgCl₂.