Digital Processing for Single Nanoparticle Electrochemical Transient Measurements
Digital Processing for Single Nanoparticle Electrochemical Transient Measurements
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单纳米颗粒电化学瞬态测量的数字处理
DOI：
10.1021/acs.analchem.9b05238
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发表时间：
2020
影响因子：
7.4
通讯作者：
Alpuche-Aviles, Mario A.
中科院分区：
文献类型：
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作者：
Gutierrez-Portocarrero, Salvador;Sauer, Kiley;Karunathilake, Nelum;Subedi, Pradeep;Alpuche-Aviles, Mario A.
我们演示了在单个纳米颗粒电化学检测中使用数字频率分析。该方法使用快速傅立叶变换（FFT）的单实体电化学瞬态和数字滤波器。这些滤波器有效地去除噪声，与矩形滤波器相比，巴特沃思滤波器保持基本过程的幅度。在三种不同类型的实验中进行过滤：单个纳米颗粒电催化放大，光催化放大和单个实体的纳米影响。在单个纳米颗粒的阶跃瞬态中，低通滤波器保持阶跃高度。此外，如果带阻截止频率与纳米颗粒/电极瞬态相互作用相容，则巴特沃思带阻滤波器保留了尖峰瞬态中的峰高。在单个Au纳米颗粒的肼氧化中，数字滤波不会使阶跃信号的分析复杂化，因为用矩形、贝塞尔和巴特沃思低通滤波器保留了逐颗粒电流的阶跃变化，并且后者使时间偏移最小化。在光电流单实体瞬态，我们证明解决一个步骤小于噪声。在光电化学装置中，背景过程是随机的，并出现在不同的频率，不一定与检测频率（fp），二氧化钛纳米粒子。这种相关性的缺乏表明背景信号具有其特征频率，并且执行后验滤波是有利的。我们还讨论了根据采样率和fp选择滤波频率。在电解ZnO的实验中，模型nano-impacts，带阻滤波器可以去除采样光谱区域内的环境噪声，同时保留电流瞬态的相关信息。我们讨论了贝塞尔和巴特沃思滤波器解决连续瞬态的限制。
We demonstrate the use of digital frequency analysis in single nanoparticle electrochemical detection. The method uses fast Fourier transforms (FFT) of single entity electrochemical transients and digital filters. These filters effectively remove noise with the Butterworth filter preserving the amplitude of the fundamental processes in comparison with the rectangle filter. Filtering was done in three different types of experiments: single nanoparticle electrocatalytic amplification, photocatalytic amplification, and nanoimpacts of single entities. In the individual nanoparticle stepwise transients, low-pass filters maintain the step height. Furthermore, a Butterworth band-stop filter preserves the peak height in blip transients if the band-stop cutoff frequencies are compatible with the nanoparticle/electrode transient interactions. In hydrazine oxidation by single Au nanoparticles, digital filtering does not complicate the analysis of the step signal because the stepwise change of the particle-by-particle current is preserved with the rectangle, Bessel and Butterworth low pass filters, with the later minimizing time shifts. In the photocurrent single entity transients, we demonstrate resolving a step smaller than the noise. In photoelectrochemical setups, the background processes are stochastic and appear at distinct frequencies that do not necessarily correlate with the detection frequency (fp), of TiO2nanoparticles. This lack of correlation indicates that background signals have their characteristic frequencies and that it is advantageous to perform filtering a posteriori. We also discuss selecting the filtering frequencies based on sampling rates andfp. In experiments electrolyzing ZnO, that model nanoimpacts, a band-stop filter can remove environmental noise within the sampling spectral region while preserving relevant information on the current transient. We discuss the limits of Bessel and Butterworth filters for resolving consecutive transients.