Approach for Discrimination and Quantification of Electroactive Species: Kinetics Difference Revealed by Higher Harmonics of Fourier Transformed Sinusoidal Voltammetry

Discrimination and quantification of electroactive species are traditionally realized by a potential difference which is mainly determined by thermodynamics. However, the resolution of this approach is limited to tens of millivolts. In this paper, we described an application of Fourier transformed sinusoidal voltammetry (FT-SV) that provides a new approach for discrimination and quantitative evaluation of electroactive species, especially thermodynamic similar ones. Numerical simulation indicates that electron transfer kinetics difference between electroactive species can be revealed by the phase angle of higher order harmonics of FT-SV, and the difference can be amplified order by order. Thus, even a very subtle kinetics difference can be amplified to be distinguishable at a certain order of harmonics. This method was verified with structurally similar ferrocene derivatives which were chosen as the model systems. Although these molecules have very close redox potential (<10 mV), discrimination and selective detection were achieved by as high as the thirteenth harmonics. The results demonstrated the feasibility and reliability of the method. It was also implied that the combination of the traditional thermodynamic method and this kinetics method can form a two-dimension resolved detection method, and it has the potential to extend the resolution of voltammetric techniques to a new level

Methods of strain number reduction.

<p>Left column, name of the strains, top column, traits of the strains. The figure shows how the number of strains was reduced. The strains were reduced sequentially one by one in each test step. However, the individual strains eliminated in each step are done randomly. The sequencing reduction was first conducted using the data of bone cross section in five replicates. Solid line indicate the strains that was taken out in the first cycle of the tests. Dashed lines indicated the strains that were eliminated in the test in the second cycle of the tests.</p

Comparison among number of strains (number of strains), criteria for levels of significant LRS, LRS level of detected QTL, and QTL confirmation in replicates with smaller number of strains.

<p>Comparison among number of strains (number of strains), criteria for levels of significant LRS, LRS level of detected QTL, and QTL confirmation in replicates with smaller number of strains.</p

Detection of peak genomic region of QTL of Cerebral cortex volumes in mice using RI strains.

<p>The numbers at the bottom of each figure indicate the megabases. Pink color lines on the top indicate the threshold for significant level. Light grey lines indicate the threshold for suggestive level. The upper panel is the peak region for QTL on Chr 6 and the lower panel is for QTL on Chr 11. The three lines of figures from the top to the bottom in each panel are results from elimination of 1, 6 and 9 strains from a total of 54 strains. Therefore, the actual number of mouse strains in these three lines of each of sub-figures (A and B) are 53, 48, and 45, from top to bottom. The peak region of the QTL was mapped to the same location in these tests. A. Test of sample reduction of the QTL on Chr 6. B. Test of sample reduction of the QTL on Chr 11.</p

Test of reliability of QTL for the phenotype of body weight of mothers (ID 10101) in rat models by sequential reduction of number of RI strains.

<p>The numbers on top of each figure indicate the number of Chrs. The numbers at the bottom of each figure indicate the megabases on the Chrs. Pink color lines indicate the level of significance and grey lines indicate the level of suggestive. The left figure on the top line shows the two major QTLs (Chr 2 and 16) were detected when the original 26 RI strains were used in the mapping. The right figure on the top line shows the genomic region of the peak region of QTL on Chr 2. The five figures on the second line show that both QTLs were detected when the strain number was reduced into 24. The rest figures of five lines (line 3 to 7) show the mapping results of the five replicates when the strain number was reduced into 21. The left figure on each of these five lines show the LRS level of QTL on Chr 2 and 16. QTL on Chr 2 reached the detectable level in each replicate while the QTL on Chr 16 did not reach the detectable level(the grey line) in replicate #1 (line 3) and 4 (line 6). Figures on the right of these five replicates show the peak region of the QTL on Chr 2 was mapped to the same location (between 162.5 Mb and 172.5 Mb).</p

Variations in Surface Morphologies, Properties, and Electrochemical Responses to Nitro-Analyte by Controlled Electropolymerization of Thiophene Derivatives

Herein, we reported the fabrication of conjugated microporous polymer (CMP) films based on three thiophene derivatives using a one-step templateless electropolymerization in dichloromethane without any surfactants. The formation of hydrophilic or hydrophobic films with specific morphology is a comprehensive result of the polymerization sites in each monomer, the polymerization rate, and the gas bubble produced in situ during the polymerization process, which can be easily controlled by the experimental conditions, such as electropolymerization method, electrolyte, and “trace water” existed in the organic solvent. Moreover, the electrochemical reduction of metronidazole as a prototypical nitro-analyte at CMP-modified glassy carbon (GC) electrode shows remarkably increased current response compared to nonmodified GC electrode. The process is demonstrated to be typical adsorption-controlled, and the hydrophobic surface of the electrode coating film is more favorable to the absorption and thus reduction of metronidazole. This work provides a new perspective and a breakthrough point for the application of CMPs in the electrochemical sensors

Test of reliability of QTL from two studies of traits of plants by sequential reduction of number of RI strains.

<p>The numbers on the left of each figure indicate the LRS. Pink color lines indicate the level of significance and grey lines indicate the level of suggestive. Five figures on the left side are the QTL locations on Chr 6 from a study of Barley phenotype (ID49919). From the top to the bottom are the results from the five replicates, each with the number of strains reduced from original 150 to 125. The yellow lines connected to the blue dots at the bottom of each figure indicate the locations of molecular markers on Chr 6. The figures on the right are the mapping results from a study of soybean phenotype (ID5). The five figures from the top to the bottom are the mapping locations from five replicates, each with the strain number reduced from 143 to 113. The numbers at the bottom of each figure indicate the megabases on the Chrs. Each figure shows the QTL peak region between 44 and 45 Mb on Chr 19.</p

Detection of peak genomic region of QTL of cross sections of femurs in mice using RI strains.

<p>The numbers on bottom of each figure indicate the megabases. Pink color lines on top indicate the threshold for significant level. Light grey lines indicate the threshold for suggestive level. From the top to the bottom panel, are the results from reduction of 1, 2, 6, 7, 8, 9, and 10 strains (with actual strain number of 45, 44, 40, 39, 38, 37, and 36 in each test) from a total of 46 strains. These figures show that the peak region of the QTL was mapped to the same location from these tests.</p

Switch over between major and minor QTL detected with different strains.

<p>The numbers on top of each figure indicate the number of chromosome. Numbers on left vertical bar indicate the LRS values. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g003" target="_blank">Figure 3A:</a> QTL on Chr2 became one of the major QTL when test was conducted with 35 strains. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g003" target="_blank">Figure 3B:</a> QTL on Chr2 became the major QTL with highest LRS score when the test was conducted with 33 strains. QTL on Chr2 became the major QTL with highest LRS score when the test was conducted with 31 strains. QTL on Chr2 became the only major QTL with highest LRS score when the test was conducted with 29 strains. QTL on Chr2 became the only detectable major QTL when the test was conducted with 27 strains.</p

Probability of detection of QTL of TNFα cytokine expression levels with different number of strains.

<p>Y-axis indicates the Probability of QTL detection (Pd). X-axis indicates the number of RI strains in the test of Pd. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g002" target="_blank">Figure 2A:</a> Pd of QTL on Chr 6 with different number of strains. QTL on Chr6 was detected at a highly significant level with original 46 strains. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g002" target="_blank">Figure 2B:</a> Pd of QTL on Chr 1 with different number of strains. QTL on Chr1 was detected at a significant level with original 46 strains. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g002" target="_blank">Figure 2C:</a> Pd of QTL on Chr 13 with different number of strains. QTL on Chr13 was detected at a suggestive level with original 46 strains. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102307#pone-0102307-g002" target="_blank">Figure 2D</a>. Rate of false positive QTL on Chr 17 as a major QTL detected from tests of different number of strains.</p