How To Determine The Content Of Akd In Paper By Pyrolysis Gas Chromatography?
Determination of unbound AKD content:
1.5 g of crushed paper sample was added to 15 ml of hexane (hexane was previously contained in a round-bottom disposable borosilicate glass tube), and the sample was heated at 70°C for 2 hours. The solvent in the glass tube was transferred to a 20 ml scintillation glass vial. The sample remaining in the glass tube was rinsed twice with 2 ml of hexane, and the rinses were combined in the scintillation glass vial. The vial was placed in a centrifugal concentrator (KD Scientific Centrifan) to evaporate the solvent. Next, 1000 μl of hexane was added to the vial to dissolve the residue; the vial cap was closed and then vortexed for 30 seconds. Subsequently, 4 μl of the solution was taken from the vial, dried in an eco-cup, and injected into the Py-GCMS to determine the amount of unbound AKD.
Determination of bound AKD content:
15 ml of 0.5N potassium hydroxide methanol solution was added to the remaining sample in the glass tube and heated at 65°C. After 90 minutes, 1.5 ml of 6M hydrochloric acid was added, and the sample was placed in the dry bath for another 30 minutes. The solution in the glass tube was then transferred to a clean 20 ml scintillation glass vial. The sample remaining in the glass tube was rinsed twice with 2 ml of potassium hydroxide methanol solution, and the rinse solution was combined into the scintillation glass vial. Next, 5 ml of toluene was added, and the cap was tightly covered and mixed with a vortex mixer. The toluene layer was transferred to another scintillation vial and evaporated in a centrifugal concentrator (KD Scientific Centrifan). Then, 1000 μl of toluene was added to the vial to dissolve the residue; the vial cap was covered and then vortexed for 30 seconds. Next, 4 μl of the solution was taken from the vial, dried in an eco-cup, and injected into the Py-GCMS to determine the amount of bound AKD.
Determination of total AKD content:
The sum of the above unbound and bound AKD is the total content of AKD in the paper.
Py-GCMS analysis method parameters:
· Py-GCMS consists of a Shimadzu GCMS-QP2010 Ultra (Kyoto, Japan) coupled to a Frontier Laboratories PY-3030 pyrolyzer (Koriyama, Japan).
· Column: UltraAlloy - 5 MS/HT (Frontier Laboratories); 30 m × 0.25 mm; inner diameter (ID) 0.25 μm
· Helium flow rate: 1 mL/min; split ratio 50
· Temperature: 40°C for 2 min; ramp to 320°C at 20°C/min; hold for 6.5 min
· Injector: 320°C; ion source 230°C; interface 320°C
· Scan range: 40 - 600 amu
· Pyrolyzer settings: oven temperature 500°C; interface 320°C; time 0.5 min
