Flow-through photometric sensor for determination of sulfonamides

Abstract

A sensor based on integration of spectrophotometric detection and retention of the product of the Bratton–Marshall reaction for the determination of sulfanilamide, sulfamethazine, sulfaquinoxaline and sulfathiazole is reported. The methods developed using this sensor in a flow injection manifold feature linear ranges for these analytes between 10 and 1200 ng ml^–1 with relative standard deviations smaller than 2.6% in all instances and they were applied to the determination of sulfonamides in spiked milk and water samples with excellent results. The two main advantages of these sensor-based methods over other automated and non-automated counterparts are enhanced sensitivity as a result of in situ concentration and avoidance of using a de-bubbler to eliminate the nitrogen produced in the flowing system.