Sequential injection titration of chloride in milk with potentiometric detection

In this work, a sequential injection system for the pseudo-titration of chloride in milk is described. Milk was directly aspirated into the system and sandwiched between two silver nitrate plugs (titrant). The aspirated zones were then propelled to the detector (Ag₂S/Ag tubular electrode), where the depletion in the titrant silver concentration (due to the formation of a AgCl precipitate) was monitored. The results obtained by the developed sequential injection titration method were not statistically different from those provided by the potentiometric reference procedure with relative standard deviations better than 3.4%. The sampling rates achieved were 17 samples per hour.