A multisyringe flow injection system coupled with a gas diffusion cell for ammonium determination

A multisyringe flow injection system for ammonium determination based on the coupling of a gas-diffusion separation cell has been developed. By using a multisyringe burette equipped with additional three-way solenoid valves, the system allows the use of different reagents or samples with further propelling into a gas-diffusion unit. Two possibilities were tested to increase the sensitivity and repetitivity: flow delay during the diffusion of the ammonia formed and use of successive flow reversals. The proposed MSFIA system is compared with the FIA and SIA techniques based on the same principle and has been validated applying the method to the determination of ammonium in environmental samples.