title: System constants for the bis(cyanopropylsiloxane)-co-methylsilarylene HP-88 and poly(siloxane) Rtx-440 stationary phases.
abstract: The solvation parameter model is used to characterize the retention properties of the bis(cyanopropylsiloxane)-co-methylsilarylene, HP-88, and poly(siloxane), Rtx-440, stationary phases over the temperature range 60-140 degrees C. HP-88 is among the most cohesive, dipolar/polarizable and hydrogen-bond basic of stationary phases for open-tubular column gas chromatography. It has no hydrogen-bond acidity or capacity for electron lone pair interactions. It exhibits similar selectivity to the poly(cyanopropylsiloxane) stationary phase SP-2340. Rtx-440 is a low-polarity, low-cohesion stationary phase with a moderate capacity for dipolar/polarizable and hydrogen-bond base interactions. It has no hydrogen-bond acidity and possesses weak electron lone pair interactions. It has unique selectivity when compared against a system constants database for 28 common stationary phase compositions. Cluster analysis indicated that the poly(cyanopropylphenyldimethylsiloxane) stationary phase containing 6% cyanopropylphenylsiloxane monomer, DB-1301, the poly(dimethyldiphenylsiloxane) stationary phase containing 20% diphenylsiloxane monomer, Rtx-20, the poly(siloxane) stationary phase of unknown composition, DB-624, and DX-1 [a mixture of poly(dimethylsiloxane) and poly(ethylene glycol) 9:1] are the closest selectivity matches in the database. The selectivity of DB-1301 and Rtx-440 are very similar for solutes with weak hydrogen-bond acidity allowing one stationary phase to be substituted for the other with likely success. For strong hydrogen-bond acids, such as phenols, DB-1301 and Rtx-440 exhibit different selectivity.
authors.affiliation: Flint Ink Corporation, Analytical Division, 4600 Arrowhead Drive, Ann Arbor, MI 48105, USA.
authors.forename: Waruna
authors.initials: W
authors.lastname: Kiridena
authors.forename: Cheryl C
authors.initials: CC
authors.lastname: Patchett
authors.forename: Wladyslaw W
authors.initials: WW
authors.lastname: Koziol
authors.forename: Colin F
authors.initials: CF
authors.lastname: Poole
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation*; D006860:Hydrogen Bonding; D008433:Mathematics; D012833:Siloxanes / Q000737:chemistry*
chemical_list: D012833:Siloxanes; C505206:bis(cyanopropylsiloxane)-co-methylsilarylene