A rapid method for determination of acid value in transformer oil by PPy modified electrode

• Published in: Journal of Central South University Vol. 21; no. 6; pp. 2202 - 2207
• Main Authors: Xiong, Ying, He, De-liang, Feng, Yong, Zhou, Zhou, Chang, Xin-yuan, Liu, Fu-rong
• Format: Journal Article
• Language: English
• Published: Heidelberg Central South University 01.06.2014
• Subjects: Engineering; Metallic Materials; polypyrrole-modified electrode; transformer oil; acid value; voltammetry
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-014-2171-5

A polypyrrole-modified glassy carbon electrode (PPy/GC electrode) was prepared and its electrocatalytic behavior towards naphthoquinone in the presence of acid was characterized by linear sweep voltammetry (LSV). A well-defined new reduction peak appeared at a more positive potential than the original reduction peak. The new reduction peak current was linearly related to the acid value (AV) of oil. Based on it, a rapid electrochemical method for determining AV of transformer oil was developed using PPy/GC electrode. A working curve was obtained in the AV range of 0.01 to 0.40 mg(KOH)·g −1 , with a sensitivity of 39.42 μA 0.5 /(mg(KOH)·g −1 ) and the detection limit of 0.0014 mg(KOH)·g −1 (signal-to-noise ratio is 3, standard deviation is 2.247%). Moreover, the proposed method has been successfully applied to AV determination of several transformer oil samples with advantages of rapidness, high sensitivity and accuracy compared to the conventional method.