Rt q bond

Photocatalytic runs were carried out in a 250 mL Pyrex photoreactor equipped with a mechanic agitator (500 rpm) and a gas inlet and outlet for gas sampling and purge. A 18W PL-L lamp (Philips, Amsterdam, The Netherlands), placed below the photoreactor, was chosen as the UVA source with a UV band of 350-410 nm centred at 370 nm (irradiance of 5 mW.cm⁻²).
We introduced 100 mL of a 1.0 vol% PA solution containing 50 mg of photocatalyst into the reactor. A continuous flow of argon (70 mL.min⁻¹) was applied through a bubbler for 6 h into the system to fully remove the ambient air. After the purge, the photoreactor was sealed and irradiated with UVA light. Every 65 min, a 2 mL aliquot of photoproduced gases in the headspace was carried by vacuum pumping into a Clarus 500 GC FID-PDHID (PerkinElmer, Waltham, MA, USA) for analysis. Products were firstly separated though a RT-Q-Bond (Restek–30 m × 0.53 mm × 20 μm) column before FID with a Polyarc methanization module. For PDHID, a RT-M5A molecular sieve (Restek–30 m × 0.32 mm × 30 μm) was added. The carrier gas was helium N60 grade (Messer, Bad Soden, Germany). For each gaseous analysis, the oven temperature was set at 50 °C rising at 20 °C/min to reach a maximum temperature of 150 °C maintained for an additional 55 min. Tests were repeated twice to ensure reproducibility.

The instrumentation used for the investigation of different multiplex injector configurations was a GC-2010 Plus gas chromatograph with a Tracera BID barrier-discharge ionization detector equipped with an external 6-port switching valve from Shimadzu (Kyoto, Japan). The column was a DB-5MS (5% phenyl-95% methyl-polysiloxane) 30 m × 0.25 mm × 0.25 μm from Agilent J&W. A GC-MS-QP2010 Plus instrument (Shimadzu) equipped with a Rt-Q-BOND (100% divinylbenzene, Restek, Bellefonte, PA, USA) PLOT (porous layer-open tubular) column of 30 m × 0.32 mm × 10 μm dimension equipped with a particle trap and a guard column was used for real sample analysis. For the laboratory-made injector, an Arduino Leonardo ETH board (RS Components, Frankfurt am Main, Germany) with a code written in-house for Arduino Software (IDE) v1.8.9 (https://www.arduino.cc/en/main/software, accessed on 30 December 2023) was used for the control of the solenoid valves. The normally open 2-way, normally closed 2-way and 3-way solenoid valves used for the work were purchased from Bürkert Austria GmbH (Vienna, Austria). Tee connectors were from VICI Valco (Schenkon, Switzerland).