## 3 Results
### Instrumental Neutron Activation Analysis (INAA) Validation
\begin{tabular}{c c c c c c c c} \hline \hline
**Element** & **Product Naidic** & \multicolumn{2}{c}{**USCS GXR-3**} & \multicolumn{2}{c}{**NIST 1633b**} \\ \cline{3-8}  & & **Found** & **Certified** & \(\Delta/z\) & **Found** & **Certified** & \(\Delta/z\) \\ \hline As & \({}^{76}\)As & 4162 \(\pm\) 389 (9.3) & 4000 \(\pm\) 430 & 41.0/24 & 53.1 \(\pm\) 64 (21.1) & 136.2 \(\pm\) 2 & -61.0/1.00 \\ Ba & \({}^{131}\)Ba & 7934 \(\pm\) 11 (2.3) & 4700 \(\pm\) 800 & 68.0/800 & 866 \(\pm\) 10 (25.5) & 709 \(\pm\) 27 & 22.1/1.00 \\ Be & \({}^{82}\)Br & & - & -/- & 3.1 \(\pm\) 07 (26.) & (2.9) & 6.9/0.21 \\ Ca & \({}^{76}\)Ca & 9970 \(\pm\) 6600 (6.6) & 141,000 \(\pm\) 6000 & -29.3/100 & 1405.0 \(\pm\) 2826 (20.0) & 15,100 \(\pm\) 600 & -68.9/0.95 \\ Ce & \({}^{142}\)Ce & 18.8 \(\pm\) 2.1 (11.2) & 16 \(\pm\) 4 & 17.5/0.00 & 157 \(\pm\) 11 (0) & (100) & -17.3/1.00 \\ Co & \({}^{60}\)Co & 47 \(\pm\) 3 (6.4) & 48 \(\pm\) 5 & -10.9/74 & 522 \(\pm\) 13 (2.5) & (50) & 44.0/0.00 \\ Cr & \({}^{51}\)Cr & 19 \(\pm\) 1 (5.3) & 19 \(\pm\) 1 & 1.1/0.42 & 1942 \(\pm\) 88 (4.5) & 1982 \(\pm\) 47 & -20.0/78 \\ Cs & \({}^{132}\)Cs & 139 \(\pm\) 12 (6.3) & 220 \(\pm\) 50 & -40.0/9.19 & 11 \(\pm\) 2 (182.2) & (11) & 3.3/0.37 \\ Eu & \({}^{132}\)Eu & 0.48 \(\pm\) 0.15 (31.2) & 0.40 \(\pm\) 0.10 & 200.0/0.06 & 41 \(\pm\) 0.2 (49) & (4.1) & 05.0/41 \\ Fe & \({}^{96}\)Fe & 200,004 \(\pm\) 52.72 (26.1) & 186,000 \(\pm\) 18,000 & 79.0/200 & 44.2/9.39 (0.8) & 77,800 \(\pm\) 2300 & -43.1/1.00 \\ Hf & \({}^{181}\)Hf & 2.5 (-) & 2.4 \(\pm\) 0.2 & 3.8/- & 6.6 \(\pm\) 0.1 (1.5) & (6.8) & -2.9/0.98 \\ La & \({}^{142}\)La & 94.4 \(\pm\) 1 (17.0) & 8.5 \(\pm\) 10 & 10.5/0.021 & 87.4 \(\pm\) 12.7 (4.9) & (94.0) & -7.0/0.99 \\ Na & \({}^{238}\)Na & 2970 (-) & 7800 \(\pm\) 400 & -61.9/- & 2010 \(\pm\) 30 & -/- \\ Nd & \({}^{137}\)Nd & & -/- & 75 \(\pm\) 5 (6.7) & (85) & -11.4/1.00 \\ Ni & \({}^{96}\)Co & 39 (-) & 55 \(\pm\) 5 & -29.4/- & 97.5 \(\pm\) 91 (0.00) & 120.6 \(\pm\) 1.8 & -19.2/0.78 \\ Rb & \({}^{96}\)Rb & 100 (-) & 116 \(\pm\) 10 & -13.8/- & 154 \(\pm\) 7 (4.5) & (140) & 10.0/0.00 \\ Sb & \({}^{124}\)Sb & 35 \(\pm\) 8 (22.9) & 40 \(\pm\) 3 & -12.5/0.86 & 6 \(\pm\) 1(6.7) & (6) & -17.0/0.90 \\ Sc & \({}^{46}\)Sc & 17 \(\pm\) 2 (11.8) & 18 \(\pm\) 1 & -3.9/- & 21.4/2.6 \(\pm\) 10 (2.0) & (41) & 3.9/0.00 \\ Se & \({}^{75}\)Se & & 0.22 \(\pm\) 0.02 & -/- & 12.54 \(\pm\) 312 (4.9) & 10.26 \(\pm\) 0.17 & 22.2/0.05 \\ Sm & \({}^{135}\)Sm & 32 (-) & 1.0 \(\pm\) 0.3 & 221.0/- & 19 \(\pm\) 1 (5.3) & (20) & -3.5/0.73 \\ Sr & \({}^{88}\)Sr & 1140 \(\pm\) 95 (8.3) & 1140 \(\pm\) 100 & 0.0/- & 101 \(\pm\) 14 & - \\ Ta & \({}^{182}\)Ta & 0.33 (-) & 0.32 \(\pm\) 0.11 & 3.1/- & 1.7 \(\pm\) 0.1 (5.9) & (1.8) & -56.1/0.00 \\ Tb & \({}^{160}\)Pb & & -/- & 2.1 \(\pm\) 0.4 (19.0) & (2.6) & -19.2/0.99 \\ \(\langle\)Th & \({}^{230}\)Pa & 2.97 \(\pm\) 0.2 (6.7) & 2.90 \(\pm\) 0.4 & 2.4/0.05 & 22.6 \(\pm\) 2.2 (2.7) & 257 \(\pm\) 1.3 & -12.1/0.99 \\ U & \({}^{230}\)Pb & 2.9 \(\pm\) 0.4 (13.8) & 3.1 \(\pm\) 0.1 & \(-\)8.1/0.84 & 8.51 \(\pm\) 1.90 (22.3) & 8.79 \(\pm\) 0.36 & -32.0/6.0 \\ W & \({}^{160}\)W & 10,800 (-) & 10,800 (-) & 10,800 (-) & 0.0/- & 7.4 \(\pm\) 0.3 (4.1) & (7.6) & -2.6/0.94 \\ Yb & \({}^{175}\)Yb & & 0.76 \(\pm\) 0.31 & -/- & 7.4 \(\pm\) 0.3 (4.1) & (7.6) & -2.6/0.94 \\ Zn & \({}^{66}\)Zn & 219 \(\pm\) 8 (3.7) & 220 \(\pm\) 70 & \(-\)0.5/0.81 & 295 \(\pm\) 13 (4.4) & (210) & 40.5/0.00 \\ \hline \hline \end{tabular}  In brackets are reported the coefficients of variation, CV (%), calculated as ratio between standard deviation and mean value \(\times\) 100.