A flow injection (FI) system for on-line microwave digestion of slurried samples with direct elemental determinations by flame atomic absorption spectrometry is described. Organically based elemental reference samples were prepared as slurries in 5% v/v HN03 and the system was optimized for slurry mass, acid strength and tube and microwave cavity geometry. Bubble formation during digestion was controlled by post-digestion cooling and pressure regulation. Comparison of direct and FI calibrations indicated no apparent loss in sensitivity. Various samples were examined and elemental recoveries for Car Fe, Mg and Zn were typically found to be in the range 94-107% with precisions of less than 4.5% relative standard deviation.The major source of error was found t o be in the dispersion of solids (

No abstract

A flow injection (FI) system for on-line microwave digestion of waste water samples with determination of total phosphate by means of colorimetric detection is described. Acidified samples are introduced into a water carrier stream and digested under continuous-flow conditions in thin-bore tubing. Following digestion, the samples are cooled on-line and then combined with further reagent streams for subsequent colorimetric detection based on the reduction of heteromolybdophosphoric acid to Molybdenum Blue as an FI peak at 690 nm. Signals from the flow-through detector are recorded as peak height on a chart recorder. Optimization of parameters such as digestion tube length, digestion tube diameter and reagent concentrations is discussed. Calibration was found to be linear up to 20 ppm of phosphate with a limit of detection of 0.10 ppm. Samples of waste water can be analysed at a rate of approximately 2 min per sample with typical sample relative standard deviations of <5% being achieved. Results for a range of samples were found to agree with those obtained by a conventional 'block' digestion autoanalyser method. The pre-treatment of samples with pyrophosphate phosphohydrolase ensured that the determination of total phosphate as orthophosphate could be achieved for samples containing pyrophosphate species.

Vitaii, G.; Berchiesi, M. A.; Berchiesi, G. J. Chem. Eng. Data 1979, 24, 169. Castellani, F.; Berchiesi, 0.; Pucckrelll, F.; Bartocci, V. J. Chem. Eng. A new apparatus has been developed for maklng vapor pressure measurements on hlgh-pressure systems. Uslng thls equlpment, we have made a large number of new total pressure measurements on the ethane-ethylene blnary from 198.15 to 278.15 K. By Integration of the general coexlstence equatlon, relatlve volatllltles have been calculated for ethane-ethylene over the entlre temperature range.

The study investigated the impact of family functioning (as measured by the Family Assessment Device) on goal attainment (as measured by a Goal Attainment Scale) and psychosocial distress (as measured by the Brief Symptom Inventory-18) among survivors of acquired brain injury in a community re-entry rehabilitation setting. The bivariate analysis suggests that participants had significantly greater goal attainment scores if they were members of families with stronger general functioning (r = .27, p < .05), stronger defined family roles (r = .28, p < .05), a greater capacity to respond emotionally to each other (r = .29, p < .05), and proactively solved family problems (r = .28, p < .05).