GC-FID

Chromatographic Process Mechanism

Sample preparation requires the extraction of paperboard specimens using organic solvents such as ethanol, acetone, or hexane, which are subsequently injected into a capillary column lined with a stationary phase. An inert carrier gas sweeps the vaporized analytes through the heated column, separating compounds according to their boiling points, polarity, and chemical affinity for the inner stationary coating. As volatile fractions exit the column end, they enter the detector where an air-hydrogen flame pyrolyzes the carbon-bearing molecules, generating electrons and transient carbonium ions.

An applied electrical potential collects these charged particles onto an electrode plate, producing a small current proportional to the mass of carbon entering the flame. High signal linearity across multiple orders of magnitude enables precise determination of residual ink solvents, flexographic drying agents, and laminating adhesive traces.

Laboratory Testing Application

Commercial converting facilities rely on the analytical technique to verify that residual solvent retention in flexographic or gravure packaging remains beneath strict industry thresholds. European and American food packaging standards mandate that retained solvents like ethyl acetate, ethanol, and ethoxypropanol remain below five milligrams per square meter on finished folding cartons. Mineral oil aromatic hydrocarbons and mineral oil saturated hydrocarbons extracted from recycled fiber stocks undergo precise quantitative screening via coupled column methods utilizing this flame detection technology.

Packaging lots showing chromatographic peaks above contractual migration boundaries are quarantined to prevent sensory taint or toxicological exposure in packaged food. Routine calibration against known alkane standards preserves laboratory precision across continuous material batches.