Kinetic spectrophotometric determination of traces of sulfide

A method for the determination of sulfide based on the addition reaction of sulfide with magenta at pH 7 and 25 degrees C is described. The decrease in absorbance of magenta at 540 nm, its lambda(max), over a fixed time is proportional to the concentration of sulfide over the range of 25-2500 ng ml(-1). The limit of detection was found to be 15 ng ml(-1). Ten replicate analysis of a sample solution containing 1.5 mug ml(-1) sulfide gave a relative standard deviation of 0.8%. The effects of various cations and anions on sulfide determination have been reported and procedures for removal of interferences have been described.