With its all-in-one design, the new SMS-22 Sulfide Ion Measurement System from Electro-Chemical Devices, Inc., (ECD) can be quickly installed with no special tools, features user-selectable automated sequential sampling of sulfide ions in water and lowers plant technician and supply maintenance costs. Featuring automated sequential sampling, the Model C-22 Analyzer controls the sequential sampling with a combination of relays and timers. Sampling times are easily adjustable from 2 samples per hour to 10 samples per hour, and this economical system offers very low reagent consumption. The system uses a sulfide ion selective electrode (ISE) to measure the total amount of sulfide present in the sample. ISE-based S-2 measurement provides a wide measurement ranges of 0 to 5 ppm and up to 500 ppm using economical, easily replaceable electrode cartridges. It features a measuring temperature range of -5 to 50°C (20° to 120°F), accuracy to ± 20 ppb or 5 percent of reading, whichever is greater, and repeatability of ± 2 percent of reading.