Separation and determination of degradation products of acid orange 7 by capillary electrophoresis/capacitively coupled contactless conductivity detector

• Published in: Talanta (Oxford) 2013-07, Vol.111, p.54-61
• Main Authors: Wang, Xin, Xiong, Ya, Xie, Tianyao, Sharma, Virender K., Tu, Yuting, Yang, Jiannan, Tian, Shuanghong, He, Chun
• Format: Article
• Language: English
• Subjects: Acid orange 7; Azo Compounds - analysis; Azo Compounds - chemistry; Azo Compounds - isolation & purification; Benzenesulfonates - analysis; Benzenesulfonates - chemistry; Benzenesulfonates - isolation & purification; Buffers; Capacitively coupled contactless conductivity detector; Capillarity; Capillary electrophoresis; Degradation; Degradation product; Dyes; Electric Conductivity; Electric potential; Electrochemical Techniques - instrumentation; Electrochemical Techniques - methods; Electrophoresis, Capillary - instrumentation; Electrophoresis, Capillary - methods; Hydrogen Peroxide - chemistry; Iron - chemistry; Molecular Structure; Oxalic Acid - analysis; Phthalic Acids - analysis; Reproducibility of Results; Separation; Sulfonic acid; Sulfonic Acids - analysis; Time Factors; Voltage
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2013.03.032

Capillary electrophoresis (CE) with capacitively coupled contactless conductivity detector (C4D) was developed to separate azo-dyestuff acid orange 7 (AO7) and its six degradation products. The analyzed products were sulfamic acid, oxalic acid, benzenesulfonic acid, 4-hydroxybenzene sulfonic acid, phthalic acid, and 4-aminobenzene sulfonic acid. In developing the method, types and concentrations of running buffers, injecting voltage and time, and applied voltage were tested to obtain optimum conditions to analyze target compounds. The separation was successfully achieved within 10min using a fused-silica capillary under the following conditions: 20mmolL−1 acetate acid buffer, electrokinetic injection of −12kV×10s, and applied voltage of −13kV. The developed method was applied to analyze degradation products in situ during the reaction of AO7 with Fenton reagent (FeII+H2O2 at pH 4.0). •Simultaneous separation of AO7 degradation product using newly developed CE-C4D technique.•Developed CE-C4D technique is simple, fast, and sensitive.•CE-C4D technique has potential for in-situ monitoring of target compounds•Degradation of AO7 by Fenton reagent to six compounds.