PubMed · 579224
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
E Epstein. 1978-01-02. Pop bottle explosions.. https://pubmed.ncbi.nlm.nih.gov/579224/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The quantitative analysis of pure glucose solution < or = 225 mM (< or = 40.8 mg/mL) in 90/10 H2O/D2O was successfully completed in dilute aqueous solution by the WATR-CPMG method whereby the T2 of the water resonance is manipulated by the WATR method followed by elimination of the water peak by the CPMG pulse sequence. The method was applied to the quantitative analysis of total glucose in blood plasma from human subjects undergoing the oral glucose tolerance test in the teaching hospital, and the results were compared to those obtained using a standard glucose oxidase method in a hospital chemical pathology laboratory. The accuracy of the results obtained using the WATR-CPMG method were generally within 5% of the glucose oxidase method. The coefficient of variation was determined to be better than 4% using plasma samples of diabetic subjects. Application to the quantitative analysis of orange and guava juice was also successfully demonstrated.
Caffeine concentrations in beverages were determined using a simple and rapid method based on microextraction of caffeine onto the surface of a fused-silica fiber. The uncoated fiber was dipped into the beverage sample for 5 min after the addition of isotopically labeled (trimethyl 13C)caffeine. The adsorbed caffeine was then thermally desorbed in a conventional split/splitless injection port, and the concentration of caffeine was determined using gas chromatography with mass spectrometric detection. Quantitative reproducibilities were ca. 5% (relative standard deviation) and the entire scheme including sample preparation and gas chromatographic analysis was completed in ca. 15 min per sample. The potential of the microextraction technique for the analysis of flavor and fragrance compounds in non-caffeinated beverages is also demonstrated. Since no solvents or class-fractionation steps are required, the method has good potential for automation.
A sensitive and selective high pressure liquid chromatography (HPLC) procedure for the determination of sodium cyclamate in juices and preserves is presented. The method depends on the oxidation of cyclamate to cyclohexylamine, which then is converted prechromatographically into a fluorescent derivative. It is analyzed by HPLC on a C18:reversed-phase column and determined with fluorescence detection (excitation at 350 nm, emission at 440-650 nm). The detection limit of sodium cyclamate was 0.5-5 mg/kg, depending on the nature and dilution of the samples. The relative standard deviations thus obtained were +/- 1.0 to +/- 2.6%. The average recovery was 90%.