Table 1 Comparison between present results and the certified values of standard reference materials (mg kg −1 )
| Elements | Tuna Fish | Spinach | ||||
|---|---|---|---|---|---|---|
| Results Obtained | Certified Values | Error | Results Obtained | Certified Values | Error | |
| K | - | - | - | 27729 | 29030 | 2.26 |
| Ca | 9119 | 9640 | 5.41 | 14483 | 15270 | 4.92 |
| Cr | - | - | - | - | - | - |
| Mn | 2181 | 2140 | −1.92 | 69.33 | 75.90 | 0.76 |
| Fe | 39341 | 43200 | 8.93 | - | - | - |
| Ni | 8.44 | 8.00 | −5.50 | - | - | - |
| Cu | 3405 | 3420 | 0.44 | 13.30 | 12.20 | −8.98 |
| Zn | 4197 | 4180 | −0.41 | - | - | - |
| As | 1420 | 1540 | 7.79 | 0.035 | 0.038 | 9.21 |
| Se | 1.05 | 1.00 | −4.50 | 0.053 | 0.050 | 6.00 |
| Pb | 5443 | 5520 | 1.39 | - | - | - |