Determination of Aluminum in Soil Extracts by Atomic Absorption Spectroscopy Using the Heated Graphite Atomizer Furnace

Abstract

The methods currently in use for the determination of aluminum content in soil extracts are quite complicated and time-consuming. A new method using atomic absorption spectroscopy with the heated graphite atomizer furnace method (HGA method) was studied to develop a quick and easy method for the determination of aluminum content in soil extracts. 1. Experiment 1) Dried soils (see table 1) 2) Extraction of aluminum. Solutions for extraction: 1M KCl, 1M CH_3COO Na(pH4), (NH_4)_2C_2O_4(pH3.2), and a solution of 0.3M Na_3C_6H_5O_7, 1M Na HCO_3 and Na_2S_2O_4. 3) Dilution of extracted soil solutions with water to the proper volume. 4) Filtration through dry filter paper. 5) Preparation of sample solution : Al 0.1-2.5μg and H_3PO_4(1+1) 0.05 ml/ml. 6) 10-20μl of solution placed into graphite tube (P. E. 2100). 7) Measurement (wavelength 309.2nm) (see table 2). 2. Results Except for the 1M KC1 extract in which 3 out of 11 samples showed CV % of 12-16%, the CV% of all other extracts was less than 10%. (see table 9). When the HGA method was compared with the oxin method, there were no differences in regression coefficient, intersection, correlation coefficient, and passed the t-test. These results indicate that the HGA method is superior to currently-used method, being simpler and faster, yet equally accurate. Using this method, determination of aluminum content can be accomplished directly and rapidly, even if various solutions are used for aluminum extraction, (see table 10).