# Atomic Spectroscopy-Based Analysis of Heavy Metals in Seaweed Species
## 2 Atomic Spectroscopy-Based Heavy Metal Analysis Methods for Seaweed
### Atomic Mass Spectrometry
\begin{table}
\begin{tabular}{c c c c c c} \hline  & \
\begin{tabular}{c} **Northwestern** \\ **Spain**[17] \\ \end{tabular} &
\begin{tabular}{c} **Gulf of** \\ **Thessaloniki,** \\ **Aeggan Sea**[19] \\ \end{tabular} & **South Korea [60]** & **Southeast Asia [7]** & **Southeast Asia [4]** & **Greenland [24]** \\ \hline V & & 9.802–26.21 & 0.303–5.85 & 4.9–43 & \\ \hline Cr & 0.56 & 2.767–53.39 & 0.063–15.8 & 1.4–35 & 0.657–7.04 \\ \hline Mn & 19.3 & 38.88–757.4 & 5.68–58.5 & 14-379 & 3.35–36.5 \\ \hline Fe & & & 95.1–2295 & 125–14,148 & 82.2–702 \\ \hline Co & & 0.474–9.199 & 0.082–0.911 & 0.75–5.6 & \\ \hline Ni & 2.42 & 3.187–48.34 & 0.275–6.73 & 2.1–32 & 0.783–7.80 \\ \hline Cu & & 2.021–26.65 & 1.01–48.1 & 4.1–73 & 1.40–19.10 \\ \hline Zn & 70.6 & 70.39–218.6 & 11.9–137.2 & 8.2–52 & 12.3–75.5 \\ \hline As & 19.7 & 0.593–45.65 & 1.84–6.48 & 12.5–92.5 & 2.0–37 & 6.93–63.1 \\ \hline Sr & & 51.88–2223.0 & 23.9–1560 & & \\ \hline Mo & & 0.006–0.934 & 0.072–1.090 & 0.30–4.7 & \\ \hline Ag & & & & & \\ \hline \end{tabular}
\end{table} 
Table 4: Concentrations of the heavy metals in seaweed species at different geographical locations measured by ICP-MS. All values are in \(\mu\)g/g dry weight. The following data show the range of minimum and maximum values where applicable. [PERSON] et al. collected 26 seaweed samples from the Gulf of Thessaloniki, Aegean Sea. They were wet-digested with HNO3/HCLO4 (4/1) after the initial freeze-drying and grinding [19]. Multiple trace elements (As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr, U, V, and Zn) were analyzed using an ICP-MS instrument. Reference materials (one for seaweed and sediment, one for seawater) were also analyzed for validation. Concentration factors (seaweed/seawater) were calculated and the potential to use the seaweeds as biomonitors for various elements was assessed. The authors found that the accumulation levels of some elements (e.g., As and Cr) largely depends on the species, with _Cystoseira_ spp. (brown seaweeds) having the highest As concentrations and _Cladophora prolifera_ (green seaweed) having the highest Cr concentration, while the accumulation levels of other elements (particularly Cd, Co, Cr, Cu, Mn, and V) depend more on thallus morphology and growth strategy (filamentous versus sheet-like, coarsely-branched and/or thick-leather), instead of the phylogeny of the seaweed species. In a study by [PERSON] et al., 0.5 g samples of edible red and brown seaweeds (_Porphyna_ and _Laminaria_, respectively) from several countries in Europe and Asia were digested in 5 mL optimized acid mixture of HNO3 (4.5 mL) and H2O2 (0.5 mL) and analyzed for trace element (As, Cd, Co, Cr, Mo, Ni, Pb, Sb, Se, and V) concentrations [39]. The analyses were run on a Quadrupole ICP-MS instrument in standard mode. Four different concentrations of a multi-elemental standard solution containing all the elements of interest were used for calibration. Internal standards were also included in the standard solutions to correct for instrument drift and potential matrix effects. A series of solutions with increasing NaCl concentrations were used to correct for the polyatomic interferences of the elements As and V with chlorine ions, while the selected isotopes of the other elements of interest were free from any isobaric or polyatomic interferences. Assay validation was performed with biological certified reference materials (CRMs). The within-run and between-run accuracy and precision of CRMs were both within acceptable criteria. Good linearity was achieved for all the elements throughout the concentration range studied, and detection limits were comparable to those of previous studies. The authors found significant differences in metal concentrations, except for Co, Ni, and Sb, between _Porphyna_ and _Laminaria_.