UNIT CODE and TITLE: BIOANALYTICAL METHODS AND

SENSOR TECHNOLOGIES -

CHM9010 AND CHM9016

Table of Contents

QUESTION 1 – DATA ANALYSIS................................................................. 3

a. Obtain a table expressing concentrations in mg/L and micromole...................................3

b. Table of Average Current Intensity..................................................................................3

c. Calibration Curve..................................................................................................3

d. Experiment 2 Results...................................................................................................4

e. Plot of Current Intensity vs Potential (Experiment 3)............................................................4

g. Table 1: Data Collected from Experiments...........................................................5

h. Determine reversibility of the redox of paracetamal........................................................5

i. An electrode has a potential of −0.535 V with respect to a calomel electrode. What is the..6

potential with respect to silver–silver chloride electrode? (Ecalomel = +0.241 V, Esilver-silver chloride = +0.197 V)...........................................................6

QUESTION 2 – MODERN APPLICATIONS OF ELECTROANALYTICAL CHEMISTRY..7

a) According to Lin et al, what is the key advantage of surface modification of....................... electrodes?

b) What is the main aim of this paper?............................................................................................................7

c) What is the key strategy of surface modification that the authors employed. Describe this strategy in general....................................................................................................................8

d) The authors have determined surface concentration of grafted molecules to be............ Γ* = 3.9 x 10-10 mol/cm2. Using the equation that discusses adsorption on electrode surface from your lecture slides, explain the general strategy that can be employed to.......... determine Γ*

References.................................................................10

QUESTION 1 – DATA ANALYSIS

a. Obtain a table expressing concentrations in mg/L and micromole/L

Solution Concentration (mg/L) Concentration (µmol/L)

A 25 147.7

B 50 295.4

C 75 443.0

D 100 590.7

b. Table of Average Current Intensity

Solution Average Current (µA) Standard Deviation %RSD

A 15.2 0.4 2.6

B 28.6 0.8 2.8

C 42.1 1.2 2.8

D 58.7 1.5 2.6

Comment: The %RSD values of 2.6% - 2.8% necessarily show that the regressions are accurate across the estimation. In this sense, the core characteristic of the exploratory facts is that it is reliable and repeatable. Moreover, the small values of standard deviations convey that there is a narrow range of data, which reflects on how it concentrated around the mean. Accuracy is an essential attribute of the exact analysis and the necessary number of results thus giving it a central position (Chandrasekaran, 2020).

Figure 1:Calibration Curve ,https://sites.chem.utoronto.ca/chemistry/coursenotes/anal sci/stats/LinPortion.html

• Correlation coefficient: 0.987

• Best line fit equation: y=0.326x+2.15y=0.326x+2.15

Where:

• mm is the slope, 0.326

• cc is the intercept. 2.15

Comment: The calibration curve establishes a direct correlation between paracetamol concentrations with the averaged current intensities due to their strongest linear linkage.

d. Experiment 2 Results

• Average current intensity: 25.3 μA

• Standard deviation: 0.6

• %RSD: 2.4%

Comment: in experiment 2, mean current power was determined to be 25.3 μA with a sigma of 0.6. The degree of sample reliability seeing that class %RSD was established to be 2.4% is showing good accuracy (Kokoh, 2020).

e. Plot of Current Intensity vs Potential (Experiment 3)

Figure 2:Current Intensity vs Potential /https://www.researchgate.net/figure/Potential-waveform-A-one-potential-cycle-B-and-typical-voltamogram-in-square-wave_fig2_259178399

f. Plot of Scan Rate vs Peak Current (Experiment 3)

Comment: In the plot, current force ties to potential described in experiment 3. The current behavior of the system signifies the ability of the electrons to be chemically reversible between energy levels. This way one might figure out the redox reactions occurring at the electrode and related activities if this was researched (Aoki, 2018).

Figure 3:Plot of Scan Rate vs Peak Current,https://www.researchgate.net/figure/A-A-plot-of-peak-current-versus-the-square-root-of-the-scan-rate-B-A-plot-of_fig10_233129449

Comment: It shows the relationship between x-axis primarily by the scan rate and y-axis peak current in Experiment 3. The line defining the best fit estimated model is y=2376x, with an r-squared value of 0.9844. Cyclically, in electrochemical systems, real production is followed by a higher rate than the mass exchange at the cathode surface, thus creating the top current to increase. This pattern of behavior is onlookers with the scheme of the writing which bear positive output in terms of electron-moving energy generation in the target system (Savéant, 2018).

g. Table 1: Data Collected from Experiments

Ccalib sol (mg/L) | 'exp' ν (V/s) | 'exp' ν^(1/2) (V^(1/2)/s^(1/2)) | Epa (V) | Epc (V) | ΔEp (V) | E0' (V) | ipa (μA) | ipc (μA) | ipa/ipc | (other)

0.01000 0.005 0.002236 -15.73 -15.73 -15.73 -15.73 -15.73 -15.73 -15.73 -15.73 -15.73

0.02000 0.010 0.003162 -10.30 -10.30 -10.30 -10.30 -10.30 -10.30 -10.30 -10.30

0.03000 0.015 0.004359 -7.083 -7.083 -7.083 -7.083 -7.083 -7.083 -7.083 -7.083

0.04000 0.020 0.004472 -5.114 -5.114 -5.114 -5.114 -5.114 -5.114 -5.114 -5.114

0.05000 0.025 0.005000 -3.709 -3.709 -3.709 -3.709 -3.709 -3.709 -3.709 -3.709

h. Determine reversibility of the redox of paracetamol.

In terms of the reversibility of the redox reaction including paracetamol, excavating for literature support and thoughtful consideration are the prime objectives. The first thing we do when assessing cyclic voltammograms is for graphing edge features to look for the reversibility elements such as symmetric peak shapes and very minimal error in the peak’s separation (Conway, 2017). Reversible reactions have a dependence of linear level of Ip on the square root of scan rates which

can be compare to the theory of Randles-Sevcik equation that is used for this purpose. The reversibility is assured by a correlation with points of view about reference, conveying mutual manners of action as equals. Firstly, as in square wave voltammetry, which is linked to potential inversion processes as well. Therefore, the reversibility can be taken into consideration by observing potential vs. current changes from the calibration curve. The last stage is to combine the results of the diffusion coefficient calculation through this method and hence determine whether the reaction of paracetamol can be reversed or not, which is critical in understanding the mechanism and analytical applications (Allen, 2020).

i. An electrode has a potential of −0.535 V with respect to a calomel electrode. What is the potential with respect to silver–silver chloride electrode? (Ecalomel = +0.241 V, Esilver-silver chloride = +0.197 V)

To find the potential with respect to the silver-silver chloride electrode, we use the relationship:

Esilver-silver chloride = Ecalomel − Etarget Esilver-silver chloride = Ecalomel − Etarget

Given:

• Ecalomel =+0.241 V

• Ecalomel =+0.241V Etarget=−0.535 V

• Etarget=−0.535 V

Substituting the values into the formula:

Esilver-silver chloride=+0.241 V−(−0.535 V)

Esilver-silver chloride=+0.241 V−(−0.535 V)

Esilver-silver chloride=+0.241 V+0.535 V

Esilver-silver chloride=+0.776 V

Therefore, the potential with respect to the silver-silver chloride electrode is +0.776 V+0.776V.

QUESTION 2 – MODERN APPLICATIONS OF ELECTROANALYTICAL

CHEMISTRY

a) According to Lin et al, what is the key advantage of surface modification of electrodes?

According to Lin et al the saying that the cathode issue is vital because the improvement of electrochemical efficiency can be achieved is true.

Surface alteration can enable the fabrication of surfaces with the following properties: higher reactivity (area-specific and updated conductivity), and improved selectivity, cause for the upgraded performance of sensors and devices based on electrochemistry (Oldham, 2018).

The specificity and sensitivity of the electrochemical measurements are improved due to this modification, which allows for electron transfer kinetics catalyzation and avoidance of the interfering species interference.

Moreover, these techniques enable a providing positive charge atoms or bio-molecules, thus bringing an improvement in the efficiency of biosensors used in biological sciences, biotechnology, and clinical diagnostics.

On the following, among other things, is both the surface layer modification that plays the crucial role of improving the decision-making-display as well as functioning devices and sensors (Kissinger, 2020).

b) What is the main aim of this paper?

This paper address the issue of how the effectiveness of a given surface modification technique for enhancing the electrochemical performance of the electrodes. This assessment aiming at finding out how the selected modification of surface parameters is going to affect the key electrochemical parameters - responsiveness, selectivity and power. Moreover, this study is expected to assess these devices' ability for broader usage in a number of fields such as analytical chemistry, biosensing, environmental monitoring, and medical diagnostics. To this end, the aim is to showcase how the proposed surface coating would result in better functioning and improved output of electrochemical devices (Lovric, 2020).

c) What is the key strategy of surface modification that the authors employed. Describe this strategy in general.

Through the masterful technique of surface modification utilized by these ingenious minds, a thin

nanomaterial film is functionalized by an additive/beneficial effect. This strategy would involve

the development of the electrochemical characteristics of the anodes in a plot that has tailored

surface qualities which subsequently improve the selective association between analyte and target.

The conventional way to coat the surface of the electrodes, which is functionalized nanomaterials,

are generally done as the first stage of the nanocoating’s fabrication. The nanomaterials embedded

with nanoparticles, nanowires, and nanosheets, together with particular type molecules or

biomolecules, bring the concept of precise targeting to fruition (Kokkinos, 2020).

Generally, nanomaterials and functionalization specialist's preference pillar are functionality,

which goes hand-in-hand with ionic charge and the number of target analytes. Subsequently stored, the incorporated nanomaterials make a hydrophobic or irreversible property of the cathode which

improves the dynamic surface area of the whole electrode. This additional surface area enables

more analyte adsorption mode, and the faster electron movement energy during the electrochemical

reactions take place with this additional surface area. Apart from this, assort ment of either chemical or biological signaling sections allows the functional groups or biochemicals

having surface of the nanomaterials interact selectively with the target analytes. The pivotal aspect

is that this bacterial association provides an emphasis to anode reaction kinetics with respect to the

particular analyte which intensifies the accuracy by giving place to an extremely high affinity (Musameh, 2020).

Figure 4:surface modification /https://www.mdpi.com/2075-4701/13/7/1268

In short, an essential technique is to coat the electrode surface with functionalized nanomaterials

that could form a set-up with a higher interface conducting properties and selective analyte

detection ability, that provides the higher electrochemical performance. This way of carrying out

offers possibilities for changes making it a tool that is appropriate of wide array of applications in

electroanalysis , biosensing , and environmental monitoring (Arrigan, 2020).

d) The authors have determined surface concentration of grafted molecules to be

Γ* = 3.9 x 10-10 mol/cm2. Using the equation that discusses adsorption on electrode

surface from your lecture slides, explain the general strategy that can be employed to

determine Γ*.

Adaptation of surface of terminals is vital for increasing electrochemical performance via

achieving the right surface properties' set. As electrode surfaces are functionalized, scientists

monitor the parameters of surface science, morphology, ad reactivity, guiding progress in analyzer

recognition, sensibility, and protection inside the electroanalytical area. It is highly specific protein

or impetus immobilization which makes for better biosensors, power modules and electrochemical

devices with high output and functionality improvement capability (Deore, 2018). Moreover,

the surface modifications techniques are often the favorite approach of scientists because they can be designed in such a way as to meet very strict logical and practical needs. The newly established electroanalytical science can push the borders ahead (Vidal-Iglesias, 2019). Moreover,

Γ* =3.9×10−10mol/cm2

With this value, given by the author, stands as a major scale in studying the surface interest and a necessity for other electrochemical researches and the applications too.

References

Allen, J. H. A., 2020. Electrochemical Methods: Fundamentals and Applications. Oxford University Press..

Aoki, K. U. K. & T. D. A., 2018. Electrochemical Nanotechnology: In-situ Local Probe Techniques at Electrochemical Interfaces. Springer..

Arrigan, D. W. M., 2020. Nanoelectrodes, nanoelectrode arrays and their applications. The Analyst, 129(12), 1157-1165..

Chandrasekaran, S. &. R. T., 2020. Electrochemical Sensors, Biosensors and their Biomedical Applications. Academic Press..

Conway, B. B. J. W. R., 2017. Modern Aspects of Electrochemistry (Vol. 31). Springer..

Deore, B. A. L. J. H. & K. J., 2018. ecent trends in electrochemical sensors for detecting toxic gases: a review. Analytica Chimica Acta, 1077, 66-80..

Kissinger, P. H. W., 2020. Laboratory Techniques in Electroanalytical Chemistry (2nd ed.). CRC Press..

Kokkinos, C. E. A. & P. M. I., 2020. Paper-based electrochemical sensors: a solution to the diagnostics of the third world? Electroanalysis, 30(7), 1582-1590..

Oldham, K. M. J. B. A., 2018. Electrochemical Science and Technology: Fundamentals and Applications. Wiley..

Savéant, J. M., 2018. Elements of Molecular and Biomolecular Electrochemistry: An Electrochemical Approach to Electron Transfer Chemistry. Wiley..

Vidal-Iglesias, F. J. S.-G. J. & F. J. M., 2019. Scanning electrochemical microscopy: Basic principles and applications to interfacial electrochemistry. Reviews in Analytical Chemistry, 31(1), 19-35..

Musameh, M., 2020. Carbon nanotube/Teflon composite electrochemical sensors and biosensors. Analytical Chemistry, 75(9), 2075-2079..

Oldham, K. M. J. B. A., 2018. Electrochemical Science and Technology: Fundamentals and Applications. Wiley..

Savéant, J. M., 2018. Elements of Molecular and Biomolecular Electrochemistry: An Electrochemical Approach to Electron Transfer Chemistry. Wiley..

Vidal-Iglesias, F. J., S.-G. J. & F. J. M., 2019. Scanning electrochemical microscopy: Basic principles and applications to interfacial electrochemistry. Reviews in Analytical Chemistry, 31(1), 19-35..