Sensors 2026 , 26 , 2049
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Table1. Cont.
Paper Grammage (g)
Countryof Origin* Indonesia Indonesia
Year of Production
ID Type of Wood *
Market
Manufacturer
P10 P11 P12 P13 P14
Acacia Acacia
70 80 80 80 80
Germany Germany Germany
APRIL APRIL
2019 2019 2018 2019 2019
Birch
STORAENSO
Nordic
Spain Spain
TORRAS PAPEL ZINCUÑAGA THE NAVIGATOR COMPANY THE NAVIGATOR COMPANY (FIG)
Spain Spain
E. globulus E. globulus
P15
80
Portugal
Portugal
2019
E. globulus
P16
80
Portugal
Portugal
2019
E. globulus
P17 P18
Mix
80 75
- -
ARTIC PAPER
Poland?
2018 2018
-
AA
Thailand/France
CLAIRE FONTAINE FEDRIGONI
P19
E. globulus ?
80
France
France
2019
P20 P21
E. globulus ? Recycled?
80 80
Italy
Italy India
2019
Holland 2019 * Whenever information is not confirmed, an interrogation mark “?” is placed next to data. Information not known is marked with “-”. TNPL 2.3. pH of Paper Samples pH measurements were performed in the laboratory by cutting approximately 1 g of paper into small pieces and immersing them in 70 mL of distilled water for 1 h. Then, the pH value of the cold extract, unfiltered, was measured with a Crison GLP 22 pH meter with a 5014T combined glass electrode (Barcelona, Spain), following the TAPPI standard 509—Hydrogen ion concentration (pH) of paper extracts: cold extraction method [15,16]. 2.4. Sampling of VOCs Emitted from Papers Two different SPME fibers (CAR/PDMS (Carboxen/PDMS) and PDMS (polydimethyl- siloxane)) were used because no single coating extracts all compounds well. PDMS (poly- dimethylsiloxane) fiber is a single-phase, non-polar absorptive liquid-like coating, and, according to the selection guide for Supelco SPME fibers [17], its use is best for non-polar to moderately non-polar compounds, especially mid- to higher-MW semi-volatiles, because its selectivity is mostly based on hydrophobicity (partitioning into PDMS). In terms of volatiles, it is often less sensitive to very volatile, small molecules. CAR/PDMS fiber is a biphasic/porous—CAR (microporous carbon adsorbent) dispersed in PDMS—having a largely adsorptive behavior. It is best for small, highly volatile compounds (low-MW gases/VOCs), often at trace levels. In terms of selectivity, it exhibits strong “molecular sieving” when capturing small molecules, with much higher sensitivity than PDMS for very volatile analytes. Therefore, for simplicity and to reduce the number of analyses and the cost, only a CAR/PDMS fiber was used for the sensor analytical system. It was the most adequate fiber for the extraction of low-molecular-weight and very volatile analytes [8,17]. Both fibers, CAR/PDMS and PDMS were used in GC-TOF-MS analysis. Both fibers were initially conditioned according to the manufacturer’s instructions. The SPME fibers were mounted on SPME holders for manual sampling.
https://doi.org/10.3390/s26072049
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