Indirect determination of arginine by graphite furnace atomic absorption spectrometry after preconcentration on a Nafion chemically modified tungsten coil

Abstract A method for the indirect determination of arginine by graphite furnace atomic absorption spectrometry after preconcentration on a Nafion chemically modified tungsten coil is described. The mechanism is discussed. In HCl solution (pH 3.5), the exchange competition between protonated arginine and Cu 2+ on the Nafion film causes a decrease in the amount of Cu 2+ binding to the Nafion film, resulting in a decrease in the absorption signal of Cu 2+ being measured. A linear relationship between the decrease in absorbance and the concentration of arginine is obtained in the range 3.1 × 10 −8 -2.5 × 10 −7 mol 1 −1 . The relative standard deviation for ten parallel determinations is 2.3%. The detection limit is 1.3 × 10 −8 mol 1 −1 . The results for the content of arginine determined in cephradine injection are satisfactory.