Behaviour and Quantification Studies of Terbacil and Lenacil in Environmental Samples Using Cyclic and Adsorptive Stripping Voltammetry at Hanging Mercury Drop Electrode |
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Authors: | T Thriveni J Rajesh Kumar D Sujatha N Y Sreedhar |
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Institution: | (1) Electrochemical Laboratories, Department of Chemistry, Sri Venkateswara University, Tirupati, 517 502, AP, India |
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Abstract: | The cyclic voltammograms of terbacil and lenacil at the hanging mercury drop electrode showed a single well defined four electron
irreversible peak in universal buffer of pH 4.0 for both compounds. The peak potentials were shifted to more negative values
on the increase of pH of the medium, implying the involvement of protons in the electrode reaction and that the proton transfer
reaction precedes the proper electrode process. The four electron single peak may be attributed to the simultaneous reduction
of carbonyl groups present in 2 and 4 in pyrimidine ring of terbacil and lenacil to the corresponding hydroxy derivative.
Based on the interfacial adsorptive character of the terbacil and lenacil onto the mercury electrode surface, a simple sensitive
and low cost differential pulse adsorptive stripping voltammetric procedure was optimized for the analysis of terbacil and
lenacil. The optimal operational conditions of the proposed procedure were accumulation potential E
acc = −0.4 V, accumulation time t
acc = 80 s, scan rate = 40 mV s−1, pulse amplitude = 25 mV using a universal buffer pH 4.0 as a supporting electrolyte. The linear concentration range was
found to be 1.5 × 10−5 to 1.2 × 10−9 mol/l and 1.5 × 10−5 to 2.5 × 10−8 mol/l with the lower detection limit of 1.22 × 10−9 and 2.0 × 10−8 mol/l. The correlation coefficient and relative standard deviation values are found to be 0.942, 0.996, 1.64% and 1.23%,
respectively, for 10 replicants. The procedure was successfully applied for determination of terbacil and lenacil in formulations,
mixed formulations, environmental samples such as fruit samples and spiked water samples. |
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Keywords: | Terbacil Lenacil Cyclic voltammetry Adsorptive stripping voltammetry Formulations Fruit samples Spiked water samples |
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