TY - JOUR

T1 - Interrupted amperometry

T2 - An ultrasensitive technique for diffusion current measuring

AU - Belebentseva, Mariia

AU - Navolotskaya, Daria

AU - Ermakov, Sergey

AU - Moshkin, Vladimir

AU - Khustenko, Larisa

N1 - Funding Information: This work was supported by Saint Petersburg State University (grant no. 12.38.219.2015 ). Scientific researches were performed at the Educational Resource Center of Chemistry of Research park of St.Petersburg State University. The authors are grateful to Prof. Richard Compton for advising the correct English term “interrupted amperometry” for the name of the proposed technique. Publisher Copyright: © 2016 Elsevier Ltd. All rights reserved. Copyright: Copyright 2016 Elsevier B.V., All rights reserved.

PY - 2016/2/10

Y1 - 2016/2/10

N2 - One of the key aims of electroanalytical methods development is the increase in sensitivity of measurements. This communication reports about a new amperometric technique called "interrupted amperometry" that is based on periodic interruption of the measuring electrical circuit. The main feature of this method is that capacitive current is analytically useful as well as faradaic current. This enables a dramatically higher sensitivity compared to the conventional amperometry. Theoretical consideration of the proposed method as well as the design of the home-made instrumentation is presented. Iron (III) was chosen as a model analyte in this preliminary study in order to demonstrate analytical possibilities of interrupted amperometry. The theoretical limit of detection of iron (III) at a carbon rotating disk electrode was found to be 3 nM. The calibration curve is linear in the whole investigated concentration range from 0.02 to 0.38 μM and gave a value of 1.22 μA μM-1 for the sensitivity. These results were compared with the values obtained in conventional direct-current amperometry mode other conditions being the same: 0.2 μM and 0.81 nA μM-1 for the limit of detection and sensitivity, respectively. The proposed technique can be useful for titration, flow injection analysis, HPLC, amperometric sensors, potentiostatic coulometry and for amperometric measurements with ultramicroelectrodes.

AB - One of the key aims of electroanalytical methods development is the increase in sensitivity of measurements. This communication reports about a new amperometric technique called "interrupted amperometry" that is based on periodic interruption of the measuring electrical circuit. The main feature of this method is that capacitive current is analytically useful as well as faradaic current. This enables a dramatically higher sensitivity compared to the conventional amperometry. Theoretical consideration of the proposed method as well as the design of the home-made instrumentation is presented. Iron (III) was chosen as a model analyte in this preliminary study in order to demonstrate analytical possibilities of interrupted amperometry. The theoretical limit of detection of iron (III) at a carbon rotating disk electrode was found to be 3 nM. The calibration curve is linear in the whole investigated concentration range from 0.02 to 0.38 μM and gave a value of 1.22 μA μM-1 for the sensitivity. These results were compared with the values obtained in conventional direct-current amperometry mode other conditions being the same: 0.2 μM and 0.81 nA μM-1 for the limit of detection and sensitivity, respectively. The proposed technique can be useful for titration, flow injection analysis, HPLC, amperometric sensors, potentiostatic coulometry and for amperometric measurements with ultramicroelectrodes.

KW - amperometry

KW - capacitive current

KW - diffusion current

KW - iron (III)

KW - signal to noise ratio

UR - http://www.scopus.com/inward/record.url?scp=84955450968&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2016.01.010

DO - 10.1016/j.electacta.2016.01.010

M3 - Article

VL - 191

SP - 510

EP - 515

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

ER -