A two-step calibration method for evaluation high bandwidth electrochemical instrument

Abstract

• A two-step method reduces the electrochemical instrument differences for single entity electroanalysis. • The coefficients C1 and C2 calibrate the current amplitude and stochastical current distribution from nanopore-based single-molecule detection. • This method is generally applicable to all nanoelectrochemical measurements for achieving practical applications. Single-entity electrochemistry allows the ultrasensitive detection of individual entities by incorporating high bandwidth electrochemical instruments. However, differences among instruments and shielding setups cause large deviations in the recorded signals, which leads to remarkable measurement errors in practical applications. Here, we developed a two-step method to calibrate instruments differences for achieving an accurate single-entity analysis. Two coefficients C1 and C 2 were calculated with standard measurements through the model resistors of 1.00 GΩ. C1 obtained from the slope value of the current–voltage (I-V) curve is used to calibrate the shifting of the current statistic distribution. Then, C 2, assessed from the standard deviation (STD) noises, is employed to calibrate the full-width at half maximum of current statistic distributions. After applying the model single-molecule experiments of Poly(dA) 4 detection with aerolysin nanopores, we showed the effective calibration of measurement differences among four kind of high bandwidth electrochemical instruments. Therefore, this method is generally applicable to nearly all kinds of single-entity electrochemical measurements to reduce measurement errors from instrument differences.