PROBLEMS OF THE SPECIATION OF CHROMIUM IN SOIL SAMPLES

Different separation/detection methods (ion exchange, organic extracti on, spectrophotometry) and four extraction media have been compared fo r the speciation of chromium. Due to the pH dependence of these method s only the spectrophotometric method using the diphenylcarbazide react ion has proved suitable for speciation analyses. If nitric acid is use d for the initial extraction stage, problems are often encountered wit h the other method during subsequent speciation analysis. The reasons for this are discussed.