A Reconsideration of the Rohrschneider Approach for Characterizing Gas Chromatographic Liquid Phases. II. Use of Four Functional Probes

Characterization of solvent properties of gas chromatographic liquid phases

“…Different statistical techniques when applied to the data of Rohrschneider and McReynolds do not provide a definite answer. Hartkopf et al 125 found that with four test solutes [benzene, nitroethane, 1-propanol (or chloroform), and dioxane] they could reproduce Rohrschneider's results with similar accuracy to the five test solutes Rohrschneider used. Lowry et al,126 using a nearest-neighbor technique, showed that two sets of three probes and several sets of four probes gave results similar to those obtained with the first five of the test probes evaluated by It was concluded that seven probes were necessary to reproduce the retention indices, but the identity was less important than the actual number.…”

Gas chromatography

“…"Polarity indices" and "hydrophilic-lipophilic balance" values of surfactants were measured by GC (914). The Rohrschneider approach to characterizing GC liquid phases has been reconsidered recently by Hartkopf (672,673) in the light of application of solubility parameter theory and factor analysis to GC. Only four "functional probes" (two f o r hydrogen bonding) were found necessary to characterize GC liquid phases-benzene (dispersion), nitroethane (dipole orientation), n-propanol or chloroform (proton donor), and dioxane (proton acceptor)and a four-term form of the Rohrschneider equation was developed which can predict AI values with the same accuracy as Rohrschneider's five-term equation (673).…”

“…The Rohrschneider approach to characterizing GC liquid phases has been reconsidered recently by Hartkopf (672,673) in the light of application of solubility parameter theory and factor analysis to GC. Only four "functional probes" (two f o r hydrogen bonding) were found necessary to characterize GC liquid phases-benzene (dispersion), nitroethane (dipole orientation), n-propanol or chloroform (proton donor), and dioxane (proton acceptor)and a four-term form of the Rohrschneider equation was developed which can predict AI values with the same accuracy as Rohrschneider's five-term equation (673). The problem of attempting to characterize liquid phases with too few test probes as well as with too many was considered by Isenhour and co-workers (1025), and they showed that two sets of three probes and several sets of four probes gave results similar to those obtained using all five test probes originally evaluated by McReynolds.…”

Interactive effects of temperature, salt concentration, and pH on head space analysis for isolating volatile trace organics in aqueous environmental samples

“…The major applications of the solubility parameter theory have been in chromatography, reverse osmosis membrane rejection predictions, and polymer chemistry (11). The solubility parameter approach applied to the chromatographic 0003-2700/79/0351-2167S01.00/0 © 1979 American Chemical Society partitioning process is described by functional probes (methyl ethyl ketone, n-butanol, nitroethane, and dioxane) (11)(12)(13)(14).…”

“…The same appears to hold true for nitroethane (<5T = 11.0) except at alkaline pH where an aci-nitrogen effect becomes important. Methyl ethyl ketone ( = 9.5) was considered to be more of a combined polarity by Hartkopf et al (13) than of specifically dipole orientation as originally described. Dioxane ( = 10.1) and butanol ( = 12.0) have predominant proton acceptor and donor forces, respectively.…”