Spectrophotometric Determination of Thiocyanate in Human Saliva Employing Micropumping Multicommutation Flow System

A procedure based on a multicommutated approach for the determination of thiocyanate (SCN−) in human saliva is described. The method was based on the reaction of Fe(III) with SCN−, producing a red complex that was monitored at 480 nm. Under optimum experimental conditions, a linear response ranging from 0.5 to 10.0 m mol L−1 SCN− (R = 0.9991), a relative standard deviation of 1.0% (n = 10) for a sample 5 m mol L−1 SCN−, a detection limit (3σ criterion) of 50 µ mol L−1, a sampling rate of 60 determinations per hour, reagent consumption of 0.02 mg Fe(III) per determination, and a waste generation of 1.6 mL per determination were achieved.