Interference by mineral acids in inductively coupled plasma atomic emission spectrometry

Interferences caused by low concentrations of mineral acids have been investigated in inductively coupled plasma atomic emission spectrometry. There appear to be two mechanisms that lower the emission intensities: the decrease in the excitation temperature and the reduction in the aspiration rate. The former was predominant at lower concentrations of mineral acids (⩽1 M) and the latter became influential at higher acid concentrations (1 M). The excitation temperature was found to decrease in the presence of mineral acids. The decreases in emission intensities were in fair agreement with those estimated from the decreases in excitation temperature.