Separation of alditol acetates from plasticizers and other contaminants by capillary gas chromatography

Sample preparation for chromatographic analysis of food

Sampling, homogenisation and sample preparation prior to chromatographic injection of food analytes are designed to enhance accuracy and precision. The reduction of inherent errors introduced by these steps requires the analyst's attention as a matter of course. Methods and examples of minimising errors in each step are reviewed.

Composition of the cell walls of Nicotiana alata Link et Otto pollen tubes

Cell walls isolated from pollen of Nicotiana alata germinated in vitro contain glucose and arabinose as the predominant monosaccharides. Methylation analysis and cytochemical studies are consistent with the major polysaccharides being a (1→3)-β-D-glucan (callose) and an arabinan together with small amounts of cellulose. The cell walls contain 2.8% uronic acids. Alcian blue stains the pollen-tube walls intensely at the tip, indicating that acidic polysaccharides are concentrated in the tip. Synthetic aniline-blue fluorochrome is specific primarily for (1→3)-β-D-glucans and stains the pollen-tube walls, except at the tip. Protein (1.5%), containing hydroxyproline (2.4%), is present in the cell wall.

An improved procedure for the methylation analysis of oligosaccharides and polysaccharides

An improved procedure for the methylation analysis of oligosaccharides and polysaccharides is described. Steps in the procedure were examined and optimised for quantitative recovery and speed. Methylation was shown to be complete by using [14C]methyl iodide. All operations were performed in the same tube and the need to concentrate solutions containing acetylated alditols of methylated sugars was eliminated, thus minimising losses due to volatilization. The method is convenient, gives high recoveries of acetylated alditols of methylated sugars, and allows analysis of the glycosyl linkages of oligo- or poly-saccharides to be completed within a working day. A wide range of oligo- and poly-saccharides were methylated by this procedure.