Gaseous monochlorobenzene was irradiated with KrF excimer laser (248 nm) under reduced pressure. The photodecomposition was an apparent first order reaction. When the system contained no additive gas, the photolysis was found to give benzene (conversion yield: 49%) in the gas phase and many unidentified products in the solid phase. On the other hand, in the presence of oxygen, carbon dioxide (1...

inadvertently allowed to dry within or on the tip of the needle. We have been using chloroform as extracting solvent for over a year, but have not seen the problems encountered by Goudie et al. concerning detector contamination, sensitivity, and baseline noise. The baseline noise they referred to in our chromatogram is not related to the use of chloroform. The degree of noise is common to the o...

We report a case of a 56 year old woman who presented with a long history of chronic attacks of vomiting. On admission to hospital she was cachectic, and attempted parenteral nutrition induced coma. The illness was found to be due to citrullinaemia, a metabolic disorder of the urea cycle. Our patient is the oldest with this disorder so far described in the literature. The main points of the cas...

A novel method is presented for the calculation of weight chain length distribution in free radical polymerization of vinyl monomers. In the proposed method, polymerization kinetic equations and molecular weight moment equations are used in conjunction with a function that defines the weight fraction of polymer in a finite chain length interval. The entire range of molecular weight is divided i...

In this rapid TLC method of analysis for the urinary cannabinoid metabolite, 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), hydrolyzed urine specimens are aspirated through a porous, alkyl-silica extraction layer located along the lower edge of a biphasic thin-layer chromatogram; THC-COOH is simultaneously extracted from the sample and concentrated on the TLC plate for subseq...

As the oven temperature is raised at a reproducible rate, analytes are eluted and the areas under the chromatogram are recorded. Boiling points are assigned to the time axis from a calibration curve, known as the boiling-point distribution curve, based on a known mixture of normal paraffin hydrocarbons over a fixed range. These paraffin hydrocarbons serve as markers, which identify the time tha...

This work presents the results of applying genetic algorithms, in selecting the more relevant features present in chromatograms of polyphenolic compounds, obtained from a high performance liquid chromatograph with aligned photodiodes detector (HPLCDAD), of samples of Chilean red wines Cabernet Sauvignon, Carmenere and Merlot. From the 6376 points of the original chromatogram, the genetic algori...

Preparative Macromolecular Chemistry, Polymerchemie, Karlsruhe Institute of Te Karlsruhe, Germany. E-mail: christopher.ba Institut für Biologische Grenzächen, Ka Hermann-von-Helmholtz-Platz 1, 76344 Egg Leibniz-Institut für Polymerforschung Dre Germany. E-mail: [email protected] Technische Universität Dresden, 01062 Dre ARC Centre of Excellence for Electromateria Australian National University,...

Modified urinary nucleosides are potentially invaluable in cancer diagnosis, as they reflect altered RNA turnovers. High-performance liquid chromatography (HPLC) was combined with full-scan mass spectrometry, tandem mass spectrometry, MS(n) analysis and accurate mass measurements in order to identify pyrimidine nucleosides purified from urine. Potential nucleosides were assessed by their eviden...

During the past decade, technological innovations based on new knowledge of the principles underlying separations processes have transformed column liquid chromatography, the oldest chromatographic technique, into a sophisticated tool for rapidly achieving the most difficult of separations and analyses. Applications of this modern version called High Performance Liquid Chromatography (HPLC) are...