Development of a turbidimetric sequential injection system to monitor the codfish desalting process

Salt-cured codfish represents an ancient process of preservation but requires the rehydration of the codfish with the correspondent salt removal. This work describes the development of a sequential injection system for the on-line turbidimetric determination of chloride during a simulated desalting process. The samples are directly aspirated to the manifold with no need for previous off-line treatments; this was possible due to the use on an in-line dialysis process; a quantification range from 50. 0 mg/L to 20. 0 g/L was established using the same manifold configuration. For monitoring the entire process, involving several chloride determinations (ca. 10), less than 3 mL of the desalting water was needed. Furthermore, the overall reagent consumption was quite low: 0. 211 mg of AgNO3, 30. 6 mg of HNO3, and 31. 1 μg of PVA per determination. The accuracy of the system was evaluated by comparison with a potentiometric reference method. The determination rate was 28 and 31 h-1 according to the chloride concentration range. Several simulated desalting processes, under different conditions, were effectively monitored with the developed method.