## 2 Results
RT = Retention Time; MF = Match Factor; P (%) = Probability Factor (%). Figure 1: DI-SPME-GC-MS chromatograms, acquired in Total Ion Current (TIC) mode, related to _Ircinia variabilis_ (_lv_, specimen number 2) and _Sarcotragus spinosus_ (_Ss_, specimen number 2), subjected to extraction with a PA fiber after the IBCF addition. (SIM) acquisition mode for the biogenic amine identified, which was linear and in the range 0.01-1 \(\upmu\)g/mL, with correlation coefficients ranging from 0.9951 to 0.9995 (Table 3) and intercepts not significantly different from zero at 95% confidence level. The obtained within-day and between-days RSD% values were in the ranges of 3.6-6.2 and 7.2-14.3, respectively, and were not concentration dependent (according to a \(t\)-test). LODs (S/N = 3) and LOQs (S/N = 10) ranged from 0.03 to 0.95 ng/mL and from 0.1 to 3.16 ng/mL, respectively. The validation parameters obtained in the work have been resumed in Table 3.  
The average BAs concentrations estimated in both sponges are listed in Table 4. The accuracy of the determinations was assessed by the assessment of the recoveries, whose levels ranged from 85 to 99% (Table 3). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Compound** & **Ss (\(\upmu\)g/g)** & **\% Rec (\(\upmu\) = 6)** & **Iv (\(\upmu\)g/g)** & **\% Rec (\(\upmu\) = 9)** \\ \hline
2-phenylethylamine & 3.56 \(\pm\) 1.30 & 99 \(\pm\) 2 & 0.65 \(\pm\) 026 & 85 \(\pm\) 3 \\ \hline cadaverine & 41.27 \(\pm\) 20.30 & 98 \(\pm\) 3 & 0.82 \(\pm\) 0.32 & 87 \(\pm\) 4 \\ \hline histamine & 2.35 \(\pm\) 0.98 & 96 \(\pm\) 3 & 1.54 \(\pm\) 0.89 & 89 \(\pm\) 5 \\ \hline isobutylamine & 3.22 \(\pm\) 1.42 & 99 \(\pm\) 1 & & \\ \hline isopentylamine & 10.09 \(\pm\) 3.09 & 93 \(\pm\) 4 & 0.05 \(\pm\) 0.03 & 88 \(\pm\) 3 \\ \hline propylamine & 0.17 \(\pm\) 0.09 & 92 \(\pm\) 3 & & \\ \hline putrescine & 3.59 \(\pm\) 1.01 & 85 \(\pm\) 3 & 0.10 \(\pm\) 0.05 & 88 \(\pm\) 3 \\ \hline tryptamine & 7.91 \(\pm\) 2.56 & 85 \(\pm\) 3 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: BAs average concentration and recoveries for spiked sponge samples (_Sarcotragus spinosulus, Ss; Ircinia variabilis, Iv_). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**RT (min)** & **_m/z Ions (Relative Intensities)_ & **Compound** \\ \hline
4.79 \(\pm\) 0.02 & **104** (74) **160** (45) 130 (34) 86 (25) & propylamine \\ \hline
5.40 \(\pm\) 0.06 & **130** (66) **118** (34) 100 (12) 173 (5) 158 (3) & isobutylamine \\ \hline
6.76 \(\pm\) 0.07 & **132** (100) 130 (98) **118** (36) 114 (29) 187 (15) & isopentylamine \\ \hline
10.23 \(\pm\) 0.09 & **104** (100) 130 (79) **91** (76) 221 (30) 148 (18) & 2-phenylethylamine \\ \hline
12.19 \(\pm\) 0.06 & **170** (100) **130** (63) 288 (10) & putrescine \\ \hline
**12.52 \(\pm\) 0.09** & **84** (85) **130** (80) 129 (73) 302 (2) & cadaverine \\ \hline
**13.61 \(\pm\) 0.06** & **130** (100) **143** (59) 260 (19) 187 (4) & tryptamine \\ \hline
**14.58 \(\pm\) 0.07** & **194** (100) **138** (25) 238 (16) & histamine \\ \hline \hline \end{tabular}
\end{table} 
Table 2: IBCF derivates of BAs determined in sponge samples, reported in order of increasing retention time, their \(m/z\) ions, and relative intensities (fragments useful for the determination in SIM acquisition mode are shown in bold).