title: Improved Flow Modulator Construction for GC × GC with Quadrupole Mass Spectrometry.
abstract: Improvement and testing of a flow modulator for the application in comprehensive two-dimensional gas chromatography separations is the subject of the presented paper. This improved setup constructed from two independent capillary branches each consisting of a pressure regulator, a pressure sensor, a two-way solenoid valve and a microfluidic T-connector, allows an independent and easy settings of the pressures and flow velocities in the modulator and provides system flexibility in an operation without need of any component exchange. The estimated flow rates were 0.4 mL/min in the first column and 3.2 mL/min in the second column. This setup was compared with the commercial Zoex cryogenic modulator for the separation of 17 selected solvents at isothermal conditions. Modulator working conditions were optimized and its separation power was demonstrated on the analysis of a lavender extract under an application of two orthogonal capillary column sets (nonpolar-polar vs. polar-nonpolar) and temperature program. The results were evaluated by two commercial software packages and discussed with respect to the identification compliance.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Ston
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.|Toxicology Department, Institute of Forensic Medicine and Toxicology, General University Hospital in Prague and 1st Faculty of Medicine of Charles University in Prague, Prague, Czech Republic.
authors.forename: Radomir
authors.initials: R
authors.lastname: Cabala
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Vaclav Matej
authors.initials: VM
authors.lastname: Bierhanzl
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Krajicek
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Bosakova