Determination of chloride in milk using sequential injection automated conductimetry

A new conductimetric sequential injection procedure is proposed for the automatic chloride determination in milk. The preparations of milk samples are time consuming procedures. The use of a sequential injection system coupled to a dialysis camera permitted easy automation and improved process control over the parameters, giving high throughput analyses. In this work, a fast and reliable automated sample addition method is described. An untreated sample of milk (142 μl) was injected with a standard reference solution (750 μl) in a carrier stream and dialysed for the conductimetric chloride determination. Potential interferences and ideal work conditions were appraised. Data acquisition and device control were achieved by computer. Results were precise (r.s.d. <1.0%) in agreement with both the official titration procedure and with the milk standard reference materials. The system was designed for conductimetric samples addition analysis, and no major problems were observed.