Elemental mass concentration

Elemental mass concentration - One-third of each Nuclepore filter was sent to Crocker Nuclear Laboratory, University of California, Davis, for elemental analysis by particle induced X-ray emission (PIXE)(14). Masses of many elements from A1 to Pb were determined with this technique, including Si, S, K, Ca,... 

To convert the peak intensities into the elemental mass concentrations, a fundamental parameter approach is used. According to this approach, the intensity Nij of the fluorescent X-ray line i of the jth element, is related to the mass ruj of the element present in the sample... 

Receptor models are powerful tools for source apportionment of particulates because a vast amount of particulate species characterization data have been collected at many sampling sites worldwide, and because many aerosol species are primary pollutants. Most of the information available is for elemental concentrations, eg, lead, nickel, and alurninum, although more recent measurements have provided data on concentrations of ionic species and carbonaceous compounds. At a sampling (or receptor) site, the aerosol mass concentration of each species i is... 

The H and He produced in the Big Bang served as "feed stock" from which all heavier elements were later created. Less than 1% of the H produced in the Big Bang has been consumed by subsequent element production and thus heavy elements are rare. Essentially all of the heavier elements now in the Earth were produced after the Big Bang inside stars. Following the Big Bang, the universe expanded to the point where instabilities formed galaxies, mass concentrations from which up to stars could develop. 

Analysis is most frequently done qualitatively since there are problems in quantification (Reed, 1973). Although intensity is approximately proportional to mass concentration of a given element there are significant deviations, depending on which other elements are present. 

The law of pollutant mass concentration for a representative element can be written over a small time step as ... 

Elderfield and Greaves [629] have described a method for the mass spectromet-ric isotope dilution analysis of rare earth elements in seawater. In this method, the rare earth elements are concentrated from seawater by coprecipitation with ferric hydroxide and separated from other elements and into groups for analysis by anion exchange [630-635] using mixed solvents. Results for synthetic mixtures and standards show that the method is accurate and precise to 1% and blanks are low (e.g., 1() 12 moles La and 10 14 moles Eu). The method has been applied to the determination of nine rare earth elements in a variety of oceanographic samples. Results for North Atlantic Ocean water below the mixed layer are (in 10 12 mol/kg) 13.0 La, 16.8 Ce, 12.8 Nd, 2.67 Sm, 0.644 Eu, 3.41 Gd, 4.78 Dy, 407 Er, and 3.55 Yb, with enrichment of rare earth elements in deep ocean water by a factor of 2 for the light rare earth elements, and a factor of 1.3 for the heavy rare earth elements. 

The symbols used in Section 1.5 to describe the evolution of element i concentration in the solid and the liquid during fractional crystallization will be kept. Other parameters used in the present derivation are almost identical to those of DePaolo (1981) although reference to time, which is immaterial to the mass balance and equilibrium conditions, has been omitted. Let a be the subscript representing the assimilated material, and assume that country-rocks concentration Cj is constant. Mass balance requires... 

Although this equation reduces to an identity whenever solute-solvent interactions are embodied in the definition of the Henry s law standard state (cf section 10.2), it must be noted that K[ is the molar ratio of trace element i in the two phases and not the weight concentration ratio usually adopted in trace element geochemistry. As we will see later in this section, this double conversion (from activity ratio to molar ratio, and from molar ratio to weight concentration ratio) complicates the interpretation of natural evidence in some cases. To avoid ambiguity, we define here as conventional partition coefficients (with the same symbol K ) all mass concentration ratios, to distinguish them from molar ratios and equilibrium constants. 

Figs. 3-6. Gold and trace element geochemical concentrations with depth In DDH-WB-08-04. Values are not corrected for mass loss or gains. Higher values of Cu, Zn and As exist In the mudstones underlying the rhyolites In hole WB-08-04. 

That is, the concentration in the crystal is the same as that in the initial melt at steady state. Therefore, the growth of the crystal does not affect the mass excess or deficiency in the melt anymore, meaning that the concentration profile (in interface-fixed reference frame) in the melt is at steady state. Steady state maybe reached only for elements whose concentration in a mineral can vary non-stoichiometrically. 

Second, because of the high sensitivity of INAA, we collected such small masses of material that samples could not be conveniently weighed. Thus, most results were obtained as the mass of an element (on particles) per unit volume of air or stack gas rather than concentration In the suspended matter. Because of this, we can compute mass contributions from the sources to ambient air only with Independent knowledge of the concentration of at least one key element In particulate matter from each source e.g., of V In particulate matter from oll-flred power plants. It would be desirable to have the Information on mass concentrations however, the point of our study was the development and testing of the fundamentals of receptor models and, only Incidentally, to estimate TSP contributions from various sources. 

Elemental mass distributions were measured using the LPI-PIXE technique on September 7, 1979. A cyclone preseparator upstream of the LPI removed coarse aerosol. Some of the results are presented in Figures 6a-c. The concentration of... 

Figure 6. Mass fraction of organic (-0-) and elemental (— —) C in Detroit, Ml—aerosol in 1975. Mass is the total mass concentration of aerosol as measured by a high-volume sampler r is the correlation coefficient between organic and elemental mass fractions fr = 0.60).

The carbon analyzer has been used to analyze filters from 42 urban sites and 22 non-urban sites in the United States. These filters were obtained from the National Air Surveillance Network (NASN) filter bank for 1975. Carbon concentrations and mass fractions for Detroit, Michigan, are shown in Figures 5 and 6. Both the organic and elemental carbon concentrations are highly variable, and no seasonal trends are apparent. For this site elemental carbon constituted 38% of total aerosol carbon. Typical values for other sites ranged between 35 and 55%. 

Cass, G. R M. H. Conklin, J. J. Shah, J. J. Huntzicker, and E. S. Macias, Elemental Carbon Concentrations Estimation of and Historical Data Base, Atmos. Environ., 18, 153-162 (1983). Castaldi, M. J., and S. M. Senkan, Real-Time, Ultrasensitive Monitoring of Air Toxics by Laser Photoionization Time-of-Flight Mass Spectrometry, J. Air Waste Manage. Assoc., 48, 77-81... 

Cumulative leaching plots (cumulative mass of element leached per mass dry weight of ash vs. cumulative mass of leachate collected vs. mass dry weight of ash) for Pb, Cu, and Zn are shown in Fig. 12. The plots are constructed using measured element leachate concentrations and volumes of leachate collected. In many cases, the detection limit of the element was used as the concentration, so that the traces are conservative. Over time, the pH of leachates has dropped from about 12 to about 9. Data for Cd are not shown because of the high number of detection limit values that were observed in both the unamended and amended lysimeters. 

From the above data, calculate the mass concentration of elemental copper in the 250 pi aliquot of the sample solution. 

The most often measured property of the LRT wildfire smokes is the mass concentration of aerosol particles in fine (PM2.5) or submicron (PMi) or in fine and coarse size fraction together (PM10). The mass concentration is usually determined either with a tapered element oscillating microbalance (e.g., [19]), or with the instruments based on p-attenuation (e.g., [13]). In addition to mass concentration, real-time instruments can measure other physical properties of particles, e.g., number concentration of particles in different size fractions using a differential mobility particle sizer [13] or the optical characteristics of smoke by a nephelometer [32]. Ground-based instruments also include remote sensing instruments such as sun photometers [32],... 

Janssen NAH, Van Mansom DEM, Van Der Jagt K, Harssema H, Hoek G (1997) Mass concentration and elemental composition of airborne particulate matter at street and background locations. Atmos Environ 31 1185-1193... 

Some studies have also shown that carbonaceous material can be responsible for about 1.2-31% of the coarse fraction mass concentration of the atmospheric aerosol (Maenhaut et al., 2002 Hueglin et al., 2005). Nevertheless, the highest concentrations (17-48%) of organic matter and elemental carbon are found predominantly... 

SmoKk, J., Zdrmal, V., Schwarz, J., Lazarldis, M., Havranek, V., Eleftheriadis, K., Mihalopoulos, N., Bryant, C., and Colbeck, I., (2003). Size resolved mass concentration and elemental composition of atmospheric aerosols over the Eastern Mediterranean area. Atmos. Chem. Phys. 3,2207-2216. 

Element solutions with mass concentrations of elements of nominally 1 g/1, either as single or multi-element solutions are among the most frequently used calibrators in chemical analysis, and traceability to the SI units of the concentrations stated by the manufacturers is increasingly required. In response to this growing demand a trace-ability structure for elemental analysis is at present being set up. 

Visual range is inversely related to the atmospheric scattering coefficient, which is proportional to the fine-particle mass concentration. The two most important constituents in urban areas are elemental carbon and sulfates. 

Wall losses were estimated by comparing the mass concentrations of various elemental constituents of aerosols collected with a series of alternately collected filter and impactor samplers. For samples collected downstream of an electrostatic precipitator (ESP), where the aerosol MMAD was 11.5 pm, the average amount of mass collected in the impactors was about 60% of that collected by the filters (Table... 

Elemental mass spectrometry has undergone a major expansion in the past 15-20 years. Many new a, elopments in sample introduction systems, ionization sources, and mass analyzers have been realized. A vast array of hybrid combinations of these has resulted from specific analytical needs such as improved detection limits, precision, accuracy, elemental coverage, ease of use, throughput, and sample size. As can be seen from most of the other chapters in this volume, however, the mass analyzers used to date have primarily been magnetic sector and quadrupole mass spectrometers. Ion trapping devices, be they quadrupole ion (Paul) [1] traps or Fourier transform ion cyclotron resonance (Penning) traps, have been used quite sparingly and most work to date has concentrated on proof of principal experiments rather that actual applications. 

As fine particles arise from many sources, it would be desirable to replace the fine particle mass concentration in the equations by the concentration of an element borne by the fine particles from coal combustion and no other source. The best candidate for such an element is Se (2.4.17). If coal-fired power plants were the only significant source of Se (probably a good assumption in many areas), one could measure emission rates of SO2, SO4 and Se from the source and their concentrations at a downwind location and plug the values into the equations and solve them to obtain the conversion and deposition rates averaged over the travel time of the plume. The model is a useful first step towards the use of... 

A convenient check on the accuracy of a simulation is based on checking conserved quantities in the system. The equations of Section 6.1.3 conserve overall elemental mass balance. Thus, were the equations to be solved exactly, then the total proton, magnesium, and potassium concentrations would remain constant in time. 

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