European Journal of Biomedical and Pharmaceutical Sciences

SPECTROPHOTOMETRIC AND POTENTIOMETRIC DETERMINATION OF ANIONIC SURFACTANTS BASED ON COBALT SENSOR

Dr. Sabah M. Moltazem*

ABSTRACT

Simple, fast and sensitive potentiometric and spectrophotometric methods based on the use of cobalt phthalocyanine as molecular recognition reagent. A PVC-membrane sensor is described for flow injection analysis of anionic surfactants in some industrial products. The sensor offers the advantages of fast response, reasonable selectivity, possible interfacing with computerized and automated systems, low limit of detection, long life span and a wide pH working range. The influences of membrane composition and pH on the response of the sensor are investigated. The working response range is 8.0 × 10-7- 7.9× 10-4 M SDS with anionic Nernstian slope of 56 ± 1 mV /decade and the lower detection limit is 2.5 × 10-7 M. The proposed sensor reveals good selectivity for SDS in the presence of different anionic species. Co(II) phthalocyanine is also used as chromogen in DMSO for spectrophotometric method determination of sodium dodecyl sulphate ion. The spectrophotometric method covers the linear range of 9.9x 10-5 to 1.07 x 10-3 M.

Keywords: Phthalocyanine, Nernstian, spectrophotometric, chromogen.