INQUIRY ON TOTAL CARBON AND TOTAL NITROGEN ANALYSIS OF SOIL SAMPLES

5 soil samples derived from loess and limestone were analyzed for tota l carbon and total nitrogen by 40 different laboratories. All data of carbon analyses are within an expected range. In contrast, the nitroge n contents are overestimated by the LECO-apparatuses. The Other nitrog en values scatter - beside good reproducible with the mean value - con siderably between the different laboratories. The reasons are probably : i. incorrect adjustment of the apparatuses and ii. the regeneration status of the catalysts and the gas filters. The analysis of soil samp les requires a better adjustment of the whole instrument than the anal ysis of pure chemicals for calibration purposes.