Study of an automatically triggered digital integrator for atomic spectrometry of 15 elements using discrete nebulisation

Abstract

A signal integrator, with an automatic trigger and a voltage to frequency counter, was used in the atomic-absorption spectrometry of silver, calcium, cadmium, cobalt, copper, iron, magnesium, manganese, nickel, lead, strontium and zinc and the atomic-emission spectrometry of sodium and potassium with an air-acetylene flame and the atomic-absorption spectrometry of aluminium, calcium and magnesium with a dinitrogen oxide-acetylene flame using a discrete nebulisation technique. The effects of injection volumes, sample flow-rates and metal concentrations on the variables (peak height, integrated value, aspiration time and the ratio of the integrated value to the aspiration time) were investigated. Each of the integrated values for silver, copper, iron, magnesium, manganese and lead is proportional to the absolute amount of each metal irrespective of the metal concentration and injection volume. The calibration graphs for these six elements were straight lines passing through the origin. The relative standard deviations of the measurements were less than 4%, even with an injection volume of 20 µl, and less than 1% with an injection of 100 µl.