M. Verzele

Surface treatment, deactivation and coating in (GC)2 (glass capillary gas chromatography)

SummaryThe surface treatment, deactivation and coating of glass capillaries is discussed. Several techniques described in the literature are compared and for some critical points, new improved methods are advanced. Full details are given of optimised procedures yielding good results with every possible stationary phase. As an example, Table II mentions efficiencies of 3800 plates m−1 for OV-17 and of 1850 plates m−1 for OF-1, which hitherto was an “impossible” phase in (GC)2 (proposed abbreviation for glass capillary gas chromatography).

Sealing procedures for the static coating technique in (GC)2

SummaryA new sealing procedure for the static coating technique in (GC)2 is described. The procedure is quick and easy to carry out.

Rapid and easy HPLC analysis of amino acids

SummaryAfter transformation of amino acids to dimethylaminoazobenzenesulfonyl-(dabsyl) derivatives, these compounds are separated (in the nanomole range) by HPLC on C18-reversed phase silica gel. Separation factors (temperature, pH, buffer composition, ionic strength) are studied.

Routine steroid analysis by gas chromatography in open tubular columns

SummaryThe best approach to using glass open tubular columns in routine work is the adoption of wide bore columns and on-column injection. The technology involved is discussed using the analysis of urine steroids as an example.

Influence of the vacuum on the separation efficiency in coupled (GC)2-MS

SummaryThe van Deemter polts for the same glass capillary column one coupled to an FID detector and once to an MS instrument are compared. With full vacuum at the capillary end the column still produces 75% of the maximum attinable separation efficiency.

Sodium chloride dendrite columns in (GC)2

SummaryA method is described for roughening the surface of sodalime glass capillaries by depositing sodium chloride dendrites on the inner wall. The sodium chloride layer improves the wettability of the wall and shows favourable adsorption properties. For apolar and polar stationary phases coating efficiencies of 60 to 85% are attained.

HPLC determination of piperine in pepper and in pepper extracts

SummaryHPCL quantitation of piperine in pepper and in pepper extracts is described. This is optimised on nitratedsulphonated phenyl silica gel with phloracetophenone as internal standard.

Optimum sample size in gas chromatography

SummaryIn GC there is an optimum sample size giving the highest plate number. This is shown experimentally for preparative and normal GC columns and is probably also true for capillary column GC. Optimum sample size depends on a number of factors as discussed in the paper. It is proportionally larger for larger bore columns.

Preparative liquid chromatography: History and trends

SummaryTswett was the first to develop preparative chromatography. The evolution of this technique is sketched: from column extrusion to current day elution; from small to coarse particles and back again to small ones. Recent trends are finally pointed out.

Peak doubling in preparative liquid chromatography

SummaryPeak doublets in LC are ascribed to longitudinal column zones of different permeability leading to a double front in the column.