## 3 Results
### Test of Developed BIOS1 + BIOS2 Sensor Duplex on Real Samples and Validation with A-D Strips
\begin{table}
\begin{tabular}{c c c} \hline
**Code** & **Result with A–D Strips (ppm)** & **Result with BIOS1-BIOS2 Sensor Array (ppm)** \\ \hline Alinari sample 0 & 18.0–20.0 & 17.03 \\ \hline Alinari sample 1 & \(\leq\)0.5 & 0.455 \\ \hline Alinari sample 2 & \(\leq\)0.5 & 0.362 \\ \hline Alinari sample 3 & \(\leq\)0.5 & 0.493 \\ \hline Alinari sample 4 & 0.5–1.0 & 0.884 \\ \hline Alinari sample 5 & 0.5–1.0 & 0.94 \\ \hline Alinari sample 6 & 0.5–1.0 & 0.92 \\ \hline Alinari sample 7 & 0.5–1.0 & 1.00 \\ \hline Alinari sample 8 & \(\leq\)0.5 & 0.383 \\ \hline Alinari sample 9 & 1.0–2.0 & 1.86 \\ \hline Alinari sample 10 & 1.0–2.0 & 1.91 \\ \hline Alinari sample 11 & \(\leq\)0.5 & 0.477 \\ \hline Alinari sample 12 & \(\leq\)0.5 & 0.475 \\ \hline Alinari–B/W photo films & 0.5–1.0 & 0.815 \\ \hline Alinari–B/W photo reel & 1.0–2.0 & 1.32 \\ \hline Alinari–red hue photo films & 0.5–1.0 & 0.813 \\ \hline Alinari–color photo film & 0.5–1.0 & 0.969 \\ \hline
00010820 & \(>\)20 & \(>\)20 \\ \hline
00011242 & 0.5–1.0 & 1.034 \\ \hline
00015797 CulturArts 5 & 8–18 & 11.981 \\ \hline
00015798 CulturArts 7 & 3–5 & 2.560 \\ \hline
00015799 CulturArts 6 & 0.5–1.0 & 0.597 \\ \hline
006113 & 0.5–1.0 & 1.078 \\ \hline DFF\_12\_21 & \(\leq\)0.5 & 0.679 \\ \hline DFF\_12\_556 & \(\leq\)0.5 & 0.660 \\ \hline DFF\_12\_584 & \(\leq\)0.5 & 0.255 \\ \hline DFF\_3\_01.35.01 & \(\leq\)0.5 & \(<\)0.030 \\ \hline DFF\_3\_01.35.03 & \(\leq\)0.5 & \(<\)0.030 \\ \hline DFF\_3\_01.35.04 & \(\leq\)0.5 & \(<\)0.030 \\ \hline DFF\_3\_01.35.16 & \(\leq\)0.5 & \(<\)0.030 \\ \hline DFF\_50\_500A & \(\leq\)0.5 & 0.365 \\ \hline
88 & 1–2 & 1.099 \\ \hline
90 & \(>\)20 & 37.540 \\ \hline
94 gr Rolle & \(\leq\)0.5 & 0.417 \\ \hline
96 & \(\leq\)0.5 & 0.290 \\ \hline Carsta 62 & \(\leq\)0.5 & 0.722 \\ \hline Carsta 63 & 1–2 & 1.614 \\ \hline Carsta 64 & \(\leq\)0.5 & 0.382 \\ \hline Carsta 65 & 0.5–1 & 0.864 \\ \hline \end{tabular}
\end{table} 
Table 3: Comparison of acetic acid quantification results obtained employing official A–D strip method and developed metal oxide semiconductor (MOS) sensor array. After each measurement, the sensor was exposed to clean fresh air (no forced ventilation required) and the signal from both BIOS1 and BIOS2 sensors went back to baseline levels in less than 5 min. The good agreement obtained between data from A-D strips and acetic acid concentration calculated with the developed algorithm confirms that butanol is the only interfering vapor among those released by degrading cellulose acetate cinematographic films. As can be seen from Table 3, the results obtained with the developed array fit very well with those obtained employing the official method. BIOS1 + BIOS2 Sensor Duplex Long-Term Stability under Continuous Exposure to Cinematographic Films Vapors  
To evaluate the stability of the selected sensors when continuously exposed to the vapors released by the cinematographic films, a test was conducted by leaving six films in six different boxes, each with its own BIOS1 + BIOS2 sensor duplex installed. Acetic acid concentrations were measured at the start of the test, after 15 days and after 30 days. The results obtained are reported in Table 4.  
From the data reported, no significant variations are detected in the acetic acid concentrations calculated in the examined period.