M.B. Evans

Gas-liquid chromatography in qualitative analysis: Part II. The reproducibility of retention data in Rζ9 units

Summary The reproducibility of retention data in R ζ9 units is discussed theoretically. It is shown that high reproducibility should be readily obtainable by using suitable calibration procedures and experimental evidence in support of this is presented for a wide range of compounds.

Screen for the evaluation of chemically bonded supports used in reversed-phase high-performance liquid chromatography

Abstract A screen is proposed for the evaluation of chemically bonded supports; for use in reversed-phase high-performance liquid chromatography. Application of the screen to a range of test mixtures has revealed that, in general, octadecyl-bonded silica is the most useful.

Gas-liquid chromatography in qualitative analysis : Part. III. The constancy of ΔMe values within homologous series and relations within the periodic table

Abstract A new retention parameter, ΔMe, has been found to be constant within a homologous series with a linear temperature dependence over the limited region studied. Also regular changes in ΔMe values have been observed with substituents from the same group of the periodic table. This method should be of general application.

The flavour constituents of gin

Abstract London Dry Gin is distilled from ethanol and botanical ingredients which impart the characteristic flavour. The direct analysis of gin by gas chromatography is shown to provide very limited information. On the otehr hand, continous extraction with Freon 11 is found to yield representative flavour concentrates, suitable for analysis by gas chromatography—mass spectrometry. The principal flavour volatiles are identified.

Gas-liquid chromatography in qualitative analysis

Abstract A method of calculating RN9 values for the higher n-alkanes using the slope of the “log plot” for the n-alkanes is described.

Gas—liquid chromatography in qualitative analysis : Part V. The determination of relative retentions in Rx9 and retention index units by means of secondary standards

Abstract Procedures are described whereby relative retentinsa can be determined in Rx9 and retention index units by means of internal standards other than n-alkanes. Such procedures are important as they enable the calculation of all relative retention data in either of two simply related units.

Quantitative analysis of diastereoisomeric alkanolamines as cyclic boronic acid derivatives

Abstract Cyclic boronic derivatives formed by the interaction of bi-functional compounds and organo-boronic acids are commonly used to facilitate the gas—liquid chromatographic (GLC) analysis of diols, amino-alcohols and hydroxy compounds with adjacent primary amide moieties. When the phenylalkanolamines salmefamol and labetalol were converted to their bis-boronate derivatives irreproducible quantitative results were obtained by GLC. Because these results raise serious doubts concerning the suitability of boronic acid derivatives for quantitative analysis the factors affecting the reproducibility of the quantitative data have been investigated.