Application of the response surface methodology for potassium determination in soils by AAS using the slurry technique

The response surface methodology has been used in the analysis of soil samples in order to determine the optimum combination of the variables that have direct influence on the atomic absorption signal and to study their interactions as well as their effect on the total potassium concentration. The application of this methodology leads to a knowledge of the dependence between the analytical signal and the nitric acid concentration, time and temperature of the ultrasonic agitator. The optimum experimental responses were obtained in the isoresponse zone at 10% v/v of nitric acid, an ultrasonic time of 105 min, and a temperature of 42°C.