Sensitive disposable sensors have been constructed for potentiometric determination of Biperiden hydrochloride (BPHCl) based on multi‐walled carbon nanotubes–polyvinylchloride (MWNTs–PVC) composite in presence of dibenzo 24‐crown‐8‐ ether as a molecular receptor. Electrode matrix composition was optimized on the basis of the nature of the electroactive material, ionic sites, membrane plasticizer, and nanomaterial. The fabricated sensors showed improved selectivity and sensitivity towards biperiden hydrochloride with Nernstian cationic compliance of 59.8±1.1 mV decade−1 in the concentration range from 10−6 to 10−2 mol L−1. Modification with carbon nanotubes promote electron‐transfer processes and enhanced the stability of potential reading, response time and shelf lifetime of sensors. The proposed method was applied for potentiometric assay of BPHCl in dosage formulation and biological fluids under batch and flow injection analysis (FIA) with average recoveries agreeable with the reported official methods.

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1IntroductionSurfactants form au nique class of organic compounds which generally consist of ah ydrophilic head group and ah ydrophobic chain (or tail) [1].T he hydrophobic part is usually hydrocarbon chain (C 8 -C 18 ), while the hydrophilic group may be carboxylates,s ulfates, sulfonates (anionic), polyoxyethylenated chains (nonionic) or quaternary ammoniums alts in case of cationic surfactants [1][2][3].Thew orldwide production of surfactants was about 13 million metric tonsi n2 008;7 0% of them represent anionico nes.S urfactants are mainly employed in formulation of detergents,p ersonal-care products, paints,p esticides and textile industry [4][5][6].A fter application, surfactants are discharged into waste treatment units and then dispersed into the environment causings erious toxic effects on aquatic organismsw hen discharged with massive quantities [7][8][9].Thew idespread applications of surfactants and their environmental impacts were reflected on the development of reliable,r apid and accurate procedures for surfactanta nalysis [10][11][12][13][14][15][16][17].T wo-phaset itrationi st he most populara nalytical method for ionic surfactants in water samples [18]. Thet arget surfactant is extracted into organic solvent via formation of lipophilic ion-pair with suitable titrant in presence of an ionic dye which colors the organic layer differently at the end point. Formation of emulsion during titration,t oxicity of the chlorinated organics olvent and lack of efficiency for short chain surfactanta re the main drawbacks of such method [14].P otentiometric approaches using ion selective electrodes (ISEs) are promising option for analysis of surfactants,offering simple measuring protocol and sample pre-treatment. Surfactant potentiometric sensors are usually used as titration end-point indicator electrodes;a lthough some direct potentiometric surfactant sensors have also been reported [13,17,19,20].Liquid and PVC membranes electrodes [21,22] are inconvenient as they are mechanically complicated with difficulty of miniaturization and short lifetime. Solid-state electrodes were reported referring to an ew type of ISEs in which the internal reference elementw as in direct contact with the electroactive membrane [13,20,[23][24][25]. Elimination of the internal reference solution leads to certain advantageous such as simplicity,m iniaturization and ability to operatea th igher pressuree nvironment where the PVC membrane can be damaged.C arbon paste electrodes (CPEs) were introduced as end-point indicator electrode for potentiometric titration of surfactants [19,20] with very short response time in addition to the ease of fabrication and regeneration. However,d esigns and shapes of the aforementioned sensors were inconvenient for every purpose such as flow injection analysis or portable analyzers where the measuring unitsr equired sensors of special constructions and size.Thep ractical and economic interests have been driven the development of various kindso fd isposal electrochemical sensors based on screen-print...

Screen printing technology offers a simple and reproducible fabrication protocol for large scale production of sensors.

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