Relative Weight Fraction Research Articles

対流圏下部のエアロゾル粒子1個1個の物質組成に関するX線分析法による研究

Aerosol particles were collected with impaction technique at altitudes up to 3.0 km over three different locations in Japan: urban area (Nagoya), mountain (Mt. Norikura) and ocean (South Okinawa region). Individual aerosol particles larger than 0.5 μm in diameter (at 0 percent relative humidity) were analyzed with an electron microprobe. Elemental composition for silicon, sodium, and sulfur contained in collected particles were as follows: (1) Over Nagoya and its vicinity, the aerosol consisted often of particles rich in silicon and/or sulfur in and above mixing layer. (2) At the summit of Mt. Norikura, the aerosol consisted of particles rich in sulfur when convective activities were strong, whereas particles containing silicon and sulfur in large relative weight fractions and sodium in very small amount during nocturnal subsidence conditions. (3) Over the South Okinawa region, two regimes were clearly delineated: The aerosol consisted mainly of particles having the composition similar to the composition of sea water in marine layer, whereas particles having large relative weight fractions of silicon and/or sulfur as compared with the composition of sea water above the marine layer. The relative contribution of silicate, sea salt, and sulfate components in individual particles was estimated from the elemental composition for silicon, sodium, and sulfur contained in their particles. The result of these analysis suggests that mixed large particles (d≥0.5μm) containing silicate and sulfate in large relative weight fractions and sea salt in a minor constituent distribute widely in the free atmosphere over the Japanese Islands from Honshu to Okinawa.

Chromatographic analysis of mixtures of unknown complexity : Use of relative retention and capacity factor data

The method of optimizing column composition for the chromatographic analysis of complex mixtures of unknown composition already described by us is modified to allow use of the practical parameters: relative retention, capacity factor and weight fraction composition of a binary stationary phase. The separation of a mixture of unknown chlorinated phenols and cresols is used as an illustration.

Computer-assisted prediction of gas chromatographic separations

A computer program is presented which allows the prediction of gas-liquid chromatographic retention behavior, and, thus, the separation of complex mixtures, with binary stationary phases. The method is based upon the law of diachoric solutions, ▪ where K R is the liquid-gas partition coefficient for a solute with a stationary phase composed of a mixture of A and S of volume fractions, ⊘ A and ⊘ S , respectively; K R( A) and K R( S) are the solute partition coefficients for pure A and pure S. Computerdrawn plots of K R vs. ⊘ A and a vs. ⊘ A are used to find the optimum A + S composition which will separate a given mixture, and, in addition, predict the a value for the two most difficult solute pairs at that point. This enables the column length necessary for the baseline separation of all components to be calculated. With certain limitations, relative retention times and weight fractions, rather than partition coefficients and volume fractions, can be employed. In the examples given, a 5-component steroid mixture and a 40-component hydrocarbon mixture are virtually completely separated by the computer-assisted application of the described procedure. The only limitations to the method appear to be the turn-around time of the computer installation, and the accuracy of the K R and ⊘ A data.