ELIMINATION OF INTERFERENCES AND EFFECTS FROM DRIFT IN WORKING PARAMETERS IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY BY USING A COMBINATION OF THE GENERALIZED STANDARD ADDITION METHOD AND THE GENERALIZED INTERNAL REFERENCE METHOD

The generalized standard addition method (GSAM) and the generalized internal reference method (GIRM) were combined in a single experimental setup. This combination was used to eliminate spectral interferences and effects due to fluctuations in the system parameters when applied to systems that are flicker noise limited and that perform simultaneous multichannel measurements. p]The developed method was simplified so as to keep it within routine perspective by assuming that the applied power and nebulizer pressure are the only system parameters of which the variation could affect the precision of the method. This assumption reduced considerably the number of measurements and the mathematical calculations required by the GIRM method. The developed method was tested by measuring the alloying constituents of standard steel samples using multichannel measurements. The experimental results indicate an effective elimination of interferences and effects of drift in various experimental parameters. The precision range achieved for measured elements was 0.1-0.4% relative standard deviation. The experimental results obtained by the developed method were compared with the results obtained by the GSAM method. This comparison indicated clearly the superior performance of the developed method. The mathematical calculations required by the developed method were executed using a computer programme written in Fortran IV language and run by an NEC-750 computer. This programme is able to perform the necessary calculation in just 8 s for samples containing 20 analytes. © 1990.