# New Method for Simultaneous Arsenic and Selenium Speciation Analysis in Seafood and Onion Samples
## 2 Results and Discussion
### Simultaneous Arsenic and Selenium Speciation Analysis
Figure 1: The overlapped chromatograms of As species for HPLC–ICP–MS. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample/Determined Form** & **As(III)** & **As(V)** & **MMA** & **DMA** & **As-Bet \({}^{*}\)** & **Water-Soluble as by ICP-MS** & **Column Recovery \({}^{*}\)** \\ \hline bio white onion & 166.1 \(\pm\) 7.5 & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 0.171 \(\pm\) 0.002 & 97.7 \(\pm\) 3.7 \\ \hline pink onion & 139.2 \(\pm\) 5.6 & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 0.153 \(\pm\) 0.003 & 92.8 \(\pm\) 4.7 \\ \hline sweet onion & 149.3 \(\pm\) 5.9 & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 0.164 \(\pm\) 0.002 & 93.3 \(\pm\) 4.8 \\ \hline bio red onion & 189.3 \(\pm\) 7.9 & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 0.206 \(\pm\) 0.005 & 94.6 \(\pm\) 4.7 \\ \hline red shrimp & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 15.48 \(\pm\) 0.62 & 16.50 \(\pm\) 0.09 & 93.9 \(\pm\) 3.9 \\ \hline clam & \(<\)LOD & \(<\)LOD & \(336.9\pm 12.4\) & \(<\)LOD & 13.32 \(\pm\) 0.58 & 13.91 \(\pm\) 0.17 & 98.2 \(\pm\) 4.8 \\ \hline octopus & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 2.419 \(\pm\) 0.112 & 2.511 \(\pm\) 0.032 & 96.4 \(\pm\) 3.8 \\ \hline squid & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 4.691 \(\pm\) 0.221 & 5.011 \(\pm\) 0.061 & 93.7 \(\pm\) 4.4 \\ \hline red big shrimp & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(119.8\pm 5.5\) & 20.69 \(\pm\) 0.782 & 21.30 \(\pm\) 0.51 & 97.7 \(\pm\) 3.7 \\ \hline white blanched shrimp & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 2.507 \(\pm\) 0.100 & 2.652 \(\pm\) 0.032 & 94.6 \(\pm\) 2.7 \\ \hline Vanmarei & \(<\)LOD & \(<\)LOD & \(<\)LOD & \(<\)LOD & 2.221 \(\pm\) 0.931 & 2.304 \(\pm\) 0.027 & 96.6 \(\pm\) 4.8 \\ \hline sample/determined form & \( \begin{array}{c}\text{Se(IV)}\\ \text{Se(VI)}\\ \text{Im}\end{array} \) & \( \begin{array}{c}\text{Se(VI)}\\ \text{Se(VI)}\\ \text{Se(VI)}\\ \text{Im}\end{array} \) & \( \begin{array}{c}\text{Se-Met}\\ \text{Se(VI)}\\ \text{Se(VI)}\\ \text{Im}\end{array} \) & \(\begin{array}{c}\text{Se-Met}\\ \text{SeAnother case of this study was connected with the statement from review by [PERSON] and [PERSON] (2004), where the authors wrote that during chromatographic process can occur possibly effecting changes in arsenic species. Regarding this, they recommended to include in the research a statement about the recovery of arsenic from chromatographic columns ([PERSON], 2004). For this reason, in this study, the column (chromatographic) recovery was calculated as the ratio of the sum of the concentrations of the chromatographed species and the concentration od As and Se in the corresponding aqueous extract, analyzed by ICP-MS. We obtained the chromatographic recoveries in the range 93-97% and 92-98% for As and for Se % (onions) and 93-98% for As and 90-97% for Se (seafood). The good recovery values confirmed that the conditions of chromatographic separation in this study were efficient, and mostly all analytes were fully separated and eluted on the column(s).