High-speed analysis of residual solvents by flow-modulation gas chromatography

Rebecca E. Wittrig, Frank L. Dorman, Christopher M. English, Richard D. Sacks

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


High-speed gas chromatographic (GC) separation of residual solvents in pharmaceutical preparations, using a flow-modulation technique, is described. These volatile compounds are separated on a series-coupled (tandem) column ensemble consisting of a polyethylene glycol column and a trifluoropropylmethyl/ dimethylpolysiloxane column. This column ensemble is operated in stop-flow mode to enhance, or "tune", the separation. A valve between the junction point of the tandem column ensemble and a source of carrier gas at a pressure above the GC inlet pressure is opened for intervals of 2-8s. This stops or slightly reverses the flow of carrier gas in the first column. Stop-flow pulses are used to increase the separation of target analytes that overlap in the total ensemble chromatogram, compared to non-stop-flow, or conventional, operation. All 36 target compounds, based on ICH Classes I and II residual solvent lists, are resolved in 12min using the stop-flow technique and a single chromatographic analysis.

Original languageEnglish (US)
Pages (from-to)75-82
Number of pages8
JournalJournal of Chromatography A
Issue number1-2
StatePublished - Feb 20 2004

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry


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