David Nurok

Combined headspace and extraction technique for profile analysis by capillary gas chromatography

Abstract A method is described whereby a transevaporatoer is used for sampling 60–100 μl of aqueous sample. Volatiles are stripped from the sample either by a stream of helium and collected on a porous polymer, Tenax, or by 0.8 ml of 2-chloropropane and collected on glass beads. The volatiles are thermally desorbed into a precolumn which is connected to a capillary gas chromatographic column for analysis. The technique is shown to be reproducible and suitable for determining chromatographic profiles for a wide variety of sample types.

Determination of glucose, fructose and sucrose in molases by high-performance thin-layer chromatography

Abstract A method is described for the simultaneous determination of sucrose, fructose and glucose in molasses by high-performance thin-layer chromatography. The relative standard deviations obtained by this method are 1.1% for sucrose, 2.2% for fructose and 4.3% for glucose.

Simultaneous determination of antiarrhythmia drugs by high-performance thin-layer chromatography.

A method is described for the determination of antiarrhythmia drugs in serum by high-performance thin-layer chromatography. Baseline separations are achieved for all the drugs and clozapine, an internal standard, in two developments with solvents of different polarity. Lidocaine and diphenylhydantoin are scanned at 220 nm after the first development. Procainamide, propranolol and quinidine are scanned at 290 nm after the second development. The relative standard deviation of the determination varies between 3 and 14% depending on the nature of the drug and its concentration.

The determination of sucrose in molasses by high-performance thin-layer chromatography

A method is described for the determination of sucrose in molasses by high-performance thin-layer chromatography. A baseline separation of sucrose is achieved in about 40 min using acetone--water (90:10) as developing solvent. The relative standard deviation of determinations by this method is about 2.2%. Results agree with those obtained by isotope dilution analysis of the same molasses samples.

Separation of malto-oligosaccharides by high-performance thin-layer chromatography at moderate temperature

Abstract A procedure for the thin-layer chromatography of malto-oligosaccharides over a temperature range of 22 to 70° is described. Various mixtures of acetone, ethanol, 2-propanol and water were used as solvent. A method is proposed for estimating the temperature at which oligomers of a given degree of polymerization will be resolved.