A supported liquid membrane for microextraction of insulin, and its determination with a pencil graphite electrode modified with RuO2-graphene oxide

作者：Ensafi Ali Asghar^*; Khoddami Elaheh; Rezaei Behzad; Jafari Asl Mehdi

来源：Microchimica Acta, 2015, 182(9-10): 1599-1607.

DOI：10.1007/s00604-015-1478-8

• Insulin
• Microporous polytetrafluoroethylene membrane
• RuO2-graphene oxide-modified electrode
• Voltammetry

A new method for the microextraction and electrochemical determination of insulin is presented based on the following steps: (1) extraction of insulin from an aqueous phase (the donor phase) at pH 8.0 into a sodium dodecyl sulfate (SDS) supported liquid membrane phase to form an insulin-dodecyl sulfate complex, (2) re-extraction of insulin into a small volume of an acceptor phase at pH 3.0 (leading to preconcentration), and (3) detection by differential pulse voltammetry (DPV) using a new kind of electrode. The effects of the pH values of the donor and acceptor phases, SDS concentration, percentage of organic solvent, extraction time and ionic strength on the microextraction were optimized. A pencil graphite electrode modified with graphene oxide and ruthenium dioxide was used as an electrochemical sensor. The DPV responses to the concentration of insulin was linear in the range 0.0008-0.020 and 0.02-1.00 mu mol L-1, with a detection limit of 24 pmol L-1. The technique was successfully applied to the determination of insulin in human urine and plasma.

• 出版日期2015-7