## 4 Conclusions  
In this contribution, an electrochemical behaviour of naturally occurring tocophereols (\(\alpha\)-TOH, \(\gamma\)-TOH, and \(\delta\)-TOH) was investigated to find out optimum working conditions for their simultaneous voltammetric detection. In comparison with the previously reported scientific papers [12; 19; 23; 24], simultaneous voltammetric detection of investigated \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Concentation Ratios**}} & \multicolumn{3}{c}{**Polynomial (\%)**} & \multicolumn{3}{c}{**Linear Curve Cursor (\%)**} & \multicolumn{3}{c}{**Zero Base (\%)**} & \multicolumn{3}{c}{**Deconvolution (\%)**} \\ \multicolumn{1}{c}{**(\(\underline{\text{simol L}^{-1}}\))**} & \multicolumn{1}{c}{\(\alpha\)-TOH**} & \multicolumn{1}{c}{\(\gamma\)-TOH} & \multicolumn{1}{c}{\(\delta\)-TOH} & \multicolumn{1}{c}{\(\alpha\)-TOH} & \multicolumn{1}{c}{\(\gamma\)-TOH} & \multicolumn{1}{c}{\(\delta\)-TOH} & \multicolumn{1}{c}{\(\alpha\)-TOH} & \multicolumn{1}{c}{\(\gamma\)-TOH} & \multicolumn{1}{c}{\(\delta\)-TOH} & \multicolumn{1}{c}{\(\alpha\)-TOH} & \multicolumn{1}{c}{\(\gamma\)-TOH} & \multicolumn{1}{c}{\(\delta\)-TOH} \\ \hline
30-60-45 & 58.33 & 48.19 & 46.24 & 45.78 & 49.07 & 48.08 & 54.54 & 76.18 & 101.60 & 105.80 & 102.2 & 105.50 \\
45.7560 & 44.10 & 58.90 & 35.56 & 47.49 & 55.75 & 43.20 & 53.36 & 74.49 & 53.58 & 59.95 & 97.75 & 99.07 \\
60-90-75 & 47.70 & 54.70 & 33.97 & 49.12 & 58.31 & 40.63 & 54.90 & 72.81 & 86.07 & 80.00 & 97.84 & 99.65 \\
45.6030 & 26.38 & 65.28 & 52.15 & 30.94 & 70.77 & 55.52 & 19.52 & 62.80 & 82.41 & 81.34 & 95.18 & 118.50 \\
60-75-45 & 34.77 & 69.99 & 51.65 & 33.10 & 70.19 & 54.83 & 31.35 & 65.21 & 85.32 & 90.81 & 102.70 & 111.50 \\
75-960 & 39.80 & 66.11 & 70.97 & 32.86 & 69.92 & 61.25 & 40.30 & 65.30 & 86.73 & 79.52 & 93.64 & 106.90 \\
60-2045 & 41.91 & 55.82 & 83.20 & 43.29 & 28.60 & 88.21 & 24.57 & 68.49 & 67.75 & 73.49 & 111.70 & 101.40 \\
75-45-60 & 37.89 & 45.90 & 68.47 & 41.36 & 36.46 & 75.64 & 32.34 & 69.62 & 71.37 & 73.86 & 109.70 & 71.37 \\
90-60-75 & 38.84 & 44.02 & 61.62 & 40.54 & 39.66 & 65.31 & 36.01 & 67.25 & 69.68 & 72.03 & 100.50 & 95.57 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison evaluation methods in determination of accuracy presented as recovery values. tocopherols was simplified and significantly higher peaks separation was reached using SWV in pure MeCN at GCE and necessary low potential step of 1 mV. However, it seems that analysis of voltammetric signals is not possible without the use of mathematic decomposition (deconvolution) of overlapping peaks because standard evaluation methods included in Nova 1.11 software (polynomial and linear baseline and zero base reading) are not sufficient. Due to high precision and comparable accuracy with standard HPLC methods, it can be assumed that the present electrochemical study includes appropriate knowledge and instructions useful for the development of a direct voltammetric method for simultaneous determination of \(\alpha\)-TOH, \(\gamma\)-TOH, and \(\delta\)-TOH in different foodstuffs. The following are available online at [[https://www.mdpi.com/article/10.3390/app11178095/s1](https://www.mdpi.com/article/10.3390/app11178095/s1)]([https://www.mdpi.com/article/10.3390/app11178095/s1](https://www.mdpi.com/article/10.3390/app11178095/s1)), Figure S1: Voltammograms of 50 \(\mu\)mol L\({}^{-1}\)\(\alpha\)-TOH, \(\gamma\)-TOH, and \(\delta\)-TOH at GCE in pure MeCN containing 0.1 mol L\({}^{-1}\)LiClO\({}_{4}\) and 0.001 mol L\({}^{-1}\) CPC, SDS, or Triton X-100 at \(E_{\text{step}}\) = 1 mV, \(E_{\text{ampl}}\) = 25 mV, and \(f\) = 20 Hz. Figure S2: Comparison of voltammetric techniques in simultaneous determination of 50 \(\mu\)mol L\({}^{-1}\)\(\alpha\)-TOH, \(\gamma\)-TOH, and \(\delta\)-TOH for LSV and 10 \(\mu\)mol L\({}^{-1}\) these tocopherols for DPV and SWV. All measurements were carried out at GCE in pure MeCN containing 0.1 mol L\({}^{-1}\)LiClO\({}_{4}\).