Tenax Adsorption Bench Protocols for Differentiating Saturated and Aromatic Mineral Oils
Tenax TA vapor capture combined with LC-GC-FID and chemical epoxidation provides defensible separation of volatile MOSH and MOAH fractions in paperboard.
Carrier Gas Sweep
Stream Dynamics
Helium or nitrogen moving through a heated vaporization chamber drives the transport of volatile substances from a paper sample into the separation column. The carrier gas sweep maintains a constant flow rate to prevent sample broadening and ensure sharp peaks during chromatographic analysis. This flow carries the volatile organic compounds after they are desorbed from the fibrous matrix.
The pressure and velocity of this stream are controlled to match the requirements of the analytical column.
Extraction Efficiency
Thermal desorption units rely on the gas flow to sweep the headspace of the vial continuously during the heating cycle. Without an effective carrier gas sweep, volatile molecules would recondense on the paper fibers or the cooler surfaces of the sampling chamber. This continuous displacement shifts the equilibrium toward the gas phase, allowing complete extraction of high-boiling solvents and heavier residues.
The rate of the sweep directly determines the recovery percentage of hydrocarbon fractions from thick paperboard substrates.
Analytical Performance
Flow control determines the repeatability of the chromatographic runs. A steady carrier gas sweep yields consistent retention times and accurate quantification of ink solvents. Modern electronic flow controllers adjust the column head pressure dynamically to keep the linear velocity constant during temperature programming.