Validación de métodos analíticos para la determinación de nitrógeno asimilable y fósforo en suelo

Abstract

The present investigation project was developed in the Soil Analysis Laboratory of the Faculty of Chemical Sciences and have as a goal to validate analytical methods, for the determination of assimilable nitrogen in the form of ammoniacal nitrogen and phosphorus available for plants in the soil, through ultraviolet - visible spectrophotometry, with the purpose that in the future this laboratory offers the service to the public using validated methods, ensuring the reliability of the results. For which, a series of experiments were carried out, both to determine available phosphorus as ammoniacal nitrogen. The results from the validation of the available phosphorus determination method were: accuracy 96% recovery, precision 5% coefficient of variation; linearity 0,9999 according to the coefficient of determination (r2), limit of quantification of 0,5 ppm P. The results obtained from the validation of the ammoniacal nitrogen determination method were: accuracy 89% recovery, precision 25% coefficient of variation; linearity 0,9988 according to the coefficient of determination (r2), limit of quantification of 1 ppm N-NH4. It is important to mention that this study does not contemplate the uncertainty calculation, because it requires time and economic resources. Based on the obtained results, both analytical methods are declared validated, according to the selected validation parameters and the selected objectives