## 3 Results and Discussion
### Figures of Merit  
In order to study the linearity of the proposed method, aqueous calibration curves, calibration curves in 2% \(w/v\) sucrose and standard addition curves were constructed. Table 3 summarizes the results of the slopes, their corresponding standard deviation and the coefficients of determination of all the examined elements for the calibration curves and the standard addition curves. For all elements, the difference between the slopes of the calibration curves of aqueous solutions, the calibration curves prepared in 2% \(w/v\) and the standard addition curves were less than 10%, indicating that there is no important matrix effect due to the presence of sugar. This observation is in agreement with the results of a previous study [24]. As a result, aqueous standard solutions were chosen to evaluate method linearity. Table 4 summarizes the regression lines, the coefficients of determination, the LODs, the LOQs and the upper limits of linear range for all the examined toxic and nutrient elements that were determined from the samples. As can be observed, the LODs for all the examined elements were between 0.04 mg kg\({}^{-1}\) and 2.25 mg kg\({}^{-1}\), while the LOQs were between 0.12 mg kg\({}^{-1}\) and 7.50 mg kg\({}^{-1}\). Wide linear ranges up to 125 mg kg \({}^{-1}\) were observed for Bi, Ni, Pb and Zn, up to 500 mg kg\({}^{-1}\) for Ag, Ba, Cd, Cr, Cu, Fe and Mn and up to 2000 mg kg\({}^{-1}\) for Ca and Mg. The coefficients of determination were >0.9990, showing excellent fitness for the expected and the experimentally found values for all metals. For all metals, the linear working range ranges from the LOQ to the upper limit of the calibration curve. In order to evaluate the accuracy and the precision of the ICP-AES method, spiked samples (sample CS-2 for hard candies and sample JS-4 for jellies) at three concentration levels (25 mg kg\({}^{-1}\), 100 mg kg\({}^{-1}\) and 500 mg kg\({}^{-1}\)) were prepared and analyzed in triplicates. The results for the accuracy and the precision of the ICP-AES method are summarized in Table 5. As can be observed, the RSD values were lower than 9.0%, \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Element**} & \multirow{2}{*}{
\begin{tabular}{c} **Emission Line** \\ **(nm)** \\ \end{tabular} } & \multicolumn{4}{c}{**Matrix**} \\ \cline{3-5}  & & **Aqueous** & **2\% \(w/v\) Glucose** & **Standard Addition Curve** \\ \hline Ag & 328.068 & 249 \(\pm\) 0.2 (0.9999) & 228 \(\pm\) 0.8 (0.9999) & 236 \(\pm\) 1 (0.9999) \\ Ba & 233.527 & 19.5 \(\pm\) 0.1 (0.9999) & 17.6 \(\pm\) 0.2 (0.9999) & 18.0 \(\pm\) 0.01 (0.9999) \\ Bi & 223.061 & 3.47 \(\pm\) 0.08 (0.9994) & 3.36 \(\pm\) 0.03 (0.9999) & 3.19 \(\pm\) 0.05 (0.9998) \\ Ca & 396.847 & 29.057 \(\pm\) 50 (0.9998) & 26,684 \(\pm\) 83 (0.9998) & 27,142 \(\pm\) 41 (0.9999) \\ Cd & 226.502 & 15.6 \(\pm\) 0.03 (0.9999) & 14.2 \(\pm\) 0.1 (0.9999) & 14.1 \(\pm\) 0.01 (0.9999) \\ Co & 238.892 & 23.8 \(\pm\) 0.1 (0.9999) & 22.9 \(\pm\) 0.1 (0.9999) & 23.9 \(\pm\) 0.02 (0.9999) \\ Cr & 357.869 & 1004 \(\pm\) 4 (0.9999) & 926 \(\pm\) 1 (0.9999) & 997 \(\pm\) 4 (0.9999) \\ Cu & 324.752 & 1449 \(\pm\) 11 (0.9999) & 1382 \(\pm\) 0.2 (0.9999) & 1530 \(\pm\) 2 (0.9999) \\ Fe & 238.204 & 37.7 \(\pm\) 0.4 (0.9999) & 35.5 \(\pm\) 0.1 (0.9999) & 34.3 \(\pm\) 0.1 (0.9999) \\ Mg & 280.271 & 895 \(\pm\) 13 (0.9994) & 807 \(\pm\) 15 (0.9995) & 843 \(\pm\) 7 (0.9993) \\ Mn & 257.610 & 419 \(\pm\) 5 (0.9998) & 385 \(\pm\) 6 (0.9997) & 416 \(\pm\) 2 (0.9998) \\ Ni & 232.003 & 6.69 \(\pm\) 0.03 (0.9997) & 6.26 \(\pm\) 0.07 (0.9998) & 6.22 \(\pm\) 0.02 (0.9998) \\ Pb & 217.000 & 1.01 \(\pm\) 0.02 (0.9997) & 0.96 \(\pm\) 0.01 (0.9997) & 0.95 \(\pm\) 0.03 (0.9991) \\ Zn & 213.857 & 12.8 \(\pm\) 0.5 (0.9999) & 13.0 \(\pm\) 0.6 (0.9979) & 12.1 \(\pm\) 0.6 (0.9998) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Slope \(\pm\) standard deviation (coefficients of determination) of the different matrices.