A single novel PVC membrane for dual determination of sulphadimethoxine and malachite green in aquatic environment

A novel ion-pair of a quaternary ammonium compound; malachite green (MG), and an anionic drug sulphadimethoxine sodium (SDM) was prepared. The developed ion pair was incorporated into poly (vinyl chloride)-based membrane sensors for the dual quantification of sulphadimethoxine (sensor 1) and malachite green (sensor 2) in aquatic environment. Linear responses of SDM and MG were obtained within a concentration range of 10−5–10−2 and 10−5–10−3 M, respectively. The slopes of −29.8 ± 0.31 and 35.5 ± 0.20 mV/decade were obtained over pH range of 6–8 and 4–8 using sensors 1 and 2, in order. The proposed sensors displayed useful analytical characteristics for determination of SDM in its pharmaceutical formulation and in aquatic environment with average recoveries of 100.92 ± 0.19 and 102.47 ± 4.63, respectively. The recovery of MG in aquatic environment was 101.32 ± 3.64.