## 3 Results and Discussion
### Investigation of the Analytical Performance
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & **Cr(III)** & & **Fe(III)** & & **Co(II)** & & **Ni (II)** \\ \cline{2-10}
**Spiking Food Samples** & & & & & & & & \\ \cline{2-10}
**Food** & _Piper nigrum_ & 0.02 \(\pm\) 0.001 & - & 0.37 \(\pm\) 0.050 & - & 0.01 \(\pm\) 0.002 & - & 0.08 \(\pm\) 0.001 & - \\ \cline{2-10}
**Food** & _Vicia faba_ & 0.09 \(\pm\) 0.001 & - & BDL & - & BDL & - & 0.09 \(\pm\) 0.005 & - \\ \cline{2-10}
**Spiking** & _Piper nigrum_ & 0.200 \(\pm\) 0.017 & 100 & 0.408 \(\pm\) 0.027 & 87 & 0.104 \(\pm\) 0.019 & 97 & 0.169 \(\pm\) 0.008 & 95 \\ \cline{2-10}
**Spiking** & _Vicia faba_ & 0.191 \(\pm\) 0.016 & 99 & 0.101 \(\pm\) 0.005 & 99 & 0.104 \(\pm\) 0.024 & 99 & 0.181 \(\pm\) 0.042 & 97 \\ \cline{2-10}
**Food** & _Curcum_ & 0.197 \(\pm\) 0.021 & 100 & 0.331 \(\pm\) 0.026 & 100 & 0.104 \(\pm\) 0.055 & 99 & 0.100 \(\pm\) 0.068 & 100 \\ \cline{2-10}
**Spiking** & _Piper nigrum_ & 0.389 \(\pm\) 0.005 & 97 & 0.608 \(\pm\) 0.047 & 91 & 0.301 \(\pm\) 0.062 & 98 & 0.366 \(\pm\) 0.066 & 97 \\ \cline{2-10}
**Spiking** & _Vicia faba_ & 0.390 \(\pm\) 0.013 & 99 & 0.300 \(\pm\) 0.020 & 99 & 0.302 \(\pm\) 0.044 & 99 & 0.367 \(\pm\) 0.057 & 95 \\ \cline{2-10}
**Curcum** & 0.390 \(\pm\) 0.018 & 98 & 0.520 \(\pm\) 0.064 & 98 & 0.304 \(\pm\) 0.070 & 100 & 0.300 \(\pm\) 0.046 & 100 \\ \cline{2-10}
**Spiking** & _Piper nigrum_ & 0.690 \(\pm\) 0.034 & 99 & 0.969 \(\pm\) 0.041 & 100 & 0.596 \(\pm\) 0.049 & 98 & 0.668 \(\pm\) 0.033 & 99 \\ \cline{2-10}
**Spiking** & _Vicia faba_ & 0.690 \(\pm\) 0.048 & 100 & 0.581 \(\pm\) 0.034 & 96 & 0.594 \(\pm\) 0.026 & 98 & 0.666 \(\pm\) 0.070 & 97 \\ \cline{2-10}
**Foreum** & _Curcum_ & 0.691 \(\pm\) 0.052 & 99 & 0.821 \(\pm\) 0.030 & 99 & 0.591 \(\pm\) 0.049 & 98 & 0.597 \(\pm\) 0.094 & 99 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Addition/recovery study for the developed extraction of Cr(III), Fe(III), Co(II) and Ni(II) (n = 3). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Intraday Analysis**} & \multicolumn{6}{c}{**Interday Analysis**} \\ \cline{3-11}  & & & & & **First Day** & & & **Second Day** & & & **Third Day** \\ \cline{3-11}
**Concentration of** & & & & & & & & & & & & \\
**Standard Heavy** & & & & & & & & & & & & \\
**Metal Ion** & & & & & & & & & & & & \\
**Solution of** & & & & & & & & & & & & \\
**Co(II)** & & & & & & & & & & & & \\
**Ni(II)** & & & & & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 2: Evaluation of intraday and interday precision for Cr(III), Fe(III), Co(II) and Ni(II) (N = 8). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Coexisting** \\ **ion** \\ \end{tabular} } & \multirow{2}{*}{**Added as**} & \multicolumn{2}{c}{**Concentration**} & \multicolumn{6}{c}{**Recovery \%**} \\ \cline{3-11}  & & & & **Cr(III)** & & **Fe(III)** & & **Co(II)** & & **Ni (II)** \\ \hline
**Al\({}^{*3}\)** & Al(NO\({}_{3}\))\({}_{3}\) & 10 & 95 & 99 & 93 & 98 \\ \hline
**K\({}^{*}\)/Cl** & KCl & 2500 & 97 & 99 & 95 & 96 \\ \hline
**Pb\({}^{+2}\)** & Pb(NO\({}_{3}\))\({}_{2}\) & 10 & 96 & 98 & 93 & 93 \\ \hline
**PO\({}_{4}\)\({}^{3-}\)** & Na\({}_{3}\)PO\({}_{4}\) & 500 & 99 & 96 & 94 & 96 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Tolerance for the added foreign ions and calculated recovery percentage for Cr(III), Fe(III), Co(II) and Ni(II). Figure 7: The linearity of the addition/recovery tests from _Pipper nigrum_ samples.