Flow injection sequential determination of chloride by potentiometry and sodium by flame emission spectrometry in instant soups

A flow injection system for the sequential determination of chloride and sodium in instant soups is described. The chloride is measured with a tubular chloride ion selective electrode with a membrane consisting of a homogeneous mixture of silver chloride and silver sulfide, and the sodium is measured by flame emission spectrometry. Results were in good agreement with the reference procedures and exhibited good precision (relative standard deviations less than 1.1%). The sampling rate was 150 samples per hour.