Authors: Dan Wen Xi Zhu Faqiong Zhao Lijian Huang Baizhao Zeng
Publish Date: 2005/04/14
Volume: 10, Issue: 2, Pages: 69-77
Abstract
The voltammetric behavior of 2thiouracil at a silver electrode is described 2Thiouracil can deposit or chemisorb anodically at silver surface when the potential is made more negative the deposited 2thiouracil undergoes reductive desorptionprocess yielding a cathodic peak at about −12 V vs SCE in basic phosphate buffer solution pH 103 In the presence of cationic gemini surfactant C4H8–14C16H33N+ CH32Br−2 C16–C4–C16 the deposition of 2thiouracil is greatly improved and the cathodic peak is enhanced Meanwhile the peak shifts to more negative potential The role of C16–C4–C16 is thought to combine and coadsorb with 2thiouracil at silver surface as well as reduce the electrostatic repulse in the deposited film thus making it more easy to deposit and desorb at more negative potential With C16–C4–C16 the lateral interaction of deposits reduces the reductive desorption becomes faster and the cathodic peak becomes sharper For geminis with different spacer groups and alkyl chains their influence is mainly determined by their hydrophobicity and adsorbability It was found that increasing length of alkyl chain was favorable for obtaining a high and sharp desorption peak whose peak potential is more negative For comparison surfactants with single alkylchain and double alkylchain such as cetyltrimethyl ammonium bromide and dicetyldimethyl ammonium bromide were studied They made the desorption peak shift less due to their weaker combination with 2thiouracil
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