Abstract
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► First time we report a comparative study of F− selective PVC based sensors. ► Also first time we report the fluoride content in different brand tea samples. ► The developed sensor is superior in much aspect.
Four ligands (M1–M4) have been synthesized and characterized by IR, 1H NMR, spectroscopic investigations indicate good affinity of these ligands for fluoride anion. Different polyvinyl chloride (PVC) based membranes of ligands have been synthesized using different cationic excluders; CTAB, TDMAC, HTAB, ToMACI and plasticizers; DBBP, DBP, o-NPOE, CN, DOP, TEHB and investigated as F− selective sensors. The best performance is observed by the sensor with a membrane of composition (%, w/w) M1:PVC:o-NPOE:CTAB 3.5:30.0:63.0:3.5. The sensor generates linear potential response over a wide concentration range of 2.5×10−7 to 1.0×10−2M with Nernstian slope (59.8mVdecade−1 of activity) over a pH range of 2.5–6.5 with a fast response time of ∼11s. It shows good selectivity for fluoride anion (F−) in preference to many anions. The sensor exhibits a shelf life of two and half months and could be successfully used for the comparative determination of fluoride in different Indian tea samples. The proposed method is faster, cheaper, and more accurate in comparison to already used methods.