A Rapid Wet Digestion Method For Plant Analysis
Published 1993 · Chemistry
Analysis of nutrients in plant material requires previous digestion. Although a variety of digestion methods arc used, they are usually time-consuming procedures to digest and prepare the samples. Calcination methods, using classical muffles furnaces, allow the treatment of a high number of samples but the process requires at least 24–48 hours. Sulfuric acid based wet digestion methods, have generally the inconvenient of low Fe and Al recoveries (Bowman, 1989), and the analysis is restricted to ICP. In this work, total P, Ca, Mg, K, Fe, Mn, Zn, and Cu, in lucerne leaves (Medicago sativa L.) were determined. The solutions for analysis were prepared by an improved wet digestion method (7–8 min) based on the addition of hydrogen peroxide to the sample previously introduced in concentrated HNO3, followed by moderate heating (100 °C). Ca, Mg, Fe, Mn, Zn and Cu were determined by AAS and ICP, K, by AES, and P by colorimetry. Standard addition of iron in the leaf samples avoided the interference of HNO3 in AAS determination of Fe. The results are compared with the obtained by classical dry calcination (muffle) and other wet methods.