Filter, collection analysis

The number of fluorine equivalents (to toluene) was varied the gas and liquid flow velocities were kept constant to maintain the same flow pattern for all experiments. Liquid products were collected in an ice-cooled roimd-bottomed glass flask containing sodium fluoride to trap the hydrogen fluoride. The flask is connected to a cooling condenser to recover the solvent. Samples were typically collected for 1 h. Waste gases were scrubbed in aqueous 15% potassium hydroxide solution. Samples were degassed with nitrogen and filtered before analysis. 

For PHg, a variety of different filter methods have been applied, such as Teflon or quartz fiber filters. Before analysis, these filters undergo a wet chemical digestion usually followed by reduction-volatilization of the Hg to Hg(0) and analysis using cold vapor atomic absorbance spectrometry (CVAAS) or cold vapor atomic fluorescence spectrometry (CVAFS). Recently, a collection device based on small qrrartz... 

Gatz (8) applied a principal components analysis to aerosol composition data for St. Louis, Mo taken as part of project METROMEX (13-1 t). Nearly 400 filters collected at 12 sites were analyzed for up... 

The distribution of estimated biases for these methods is shown in Figure 3. Except for a bias of zero, the methods tend to be distributed evenly in the -10% to 10% bias region. The high proportion of zero-bias methods may be explained by the number of filter collection methods which have 100% collection efficiency many of these methods use low-biased analysis techniques, particularly atomic absorption spectroscopy. 

The detection limit for measuring a species by filter collection and subsequent analysis is determined either by the uncertainty in the filter blank, that is, the variability in the amount of a species in an unexposed filter, or by the limit of detection imposed by the analytical method. Most frequently, the limit of detection is determined by blank variability, thus care in preparation and handling of filters is important when using such systems for aircraft sampling, particularly if sampling is conducted in remote areas where concentrations are low. In this regard, it is crucial to establish the blank... 

Descriptions of analytical methods for strong acid and acidic sulfate content of atmospheric aerosols have been reviewed (6-10). Methods for acidic aerosol determination are reviewed in this chapter according to the measurement principle either filter collection and post-collection extraction, deriv-atization or thermal treatment, and analysis or in situ collection (real-time or stepwise) and analysis. 

Short HO radical lifetimes in the dark prevent the collection of ambient air samples for later analysis, except perhaps for the case of filter collection techniques that use a spin-trapping reagent (28). Furthermore, rapid reactivity of HO with surfaces mandates careful attention to the sampling train used to move ambient air into a more amenable analysis environment. 

Figure 1. Vertical concentration profiles for DMS, chlorophyll a and DMSP in the western basin of the Cariaco Trench off Venezuela (10° 39 N, 65°30 W). DMS was determined by sparging and gas chromatography with a flame photometric detector. Particulate DMSP was determined bv base treatment of material collected on 0.22 pm filters and analysis of the DMS released free DMSP was determined as DMS released upon base treatment of sparged water samples obtained after initial DMS analysis. Chlorophyll a data from W. Cooper and R. Zika (personal communication).

Filter collection, Impactor Chemical analysis of collected sample hr (colorimetric, ion-chromatography, mass spectrometry, element-specihc analysis, etc.) ... 

The multitude of PIBs produced during this process are composed of both types of input nucleocapsids. These progeny PIBs can be fed to caterpillars, initiating an infection of both virus types. The nature of the growth dynamics between the virus types can be followed in two ways. The PIBs themselves can be dissolved and their nucleocapsid components analyzed by DNA restriction enzyme digestion and subsequent filter hybridization analysis. This allows an assessment of the proportions of wild type to recombinant virus in the MC-PIB. Also, the free NOVs present in an infected caterpillar can be collected and analyzed by plaquing in cell culture. This provides an assessment of the frequency of wild type to recombinant virus free in the host. 

Air Collection on filter, direct analysis XRF 2 pg/sample No data NIOSH 1984a... 

Fig. 3 Signal profile for the analysis of Cu, Pb and Cd on a PM 10 filter collected in Boston, USA...

S. Scheme of a dilution tube system and a resonant photoacoustic cell for the investigation of exhaust partioilate the filter collection was used for chemical and mass analysis the sampling rate for the photoacoustic analysis was 1,5 1/min... 

Two types of transuranic aerosol monitoring devices are used in nuclear laboratories filter air samplers (FASs) and continuous air monitors (CAMs). The purpose of a FAS is to provide a basis for estimating the dose to workers. This is achieved by operating the FAS for a given period of time (e.g., one week), and then measuring the radioactivity collected by the filter. The analysis is performed remotely and is done... 

An aliquot is diluted with mobile phase and analysed Sample is dissolved in 95% EtOH or 0.1 M tiietbanol-amine solution for BZ4 or PBS determination respectively, and second-order derivative spectra are registered Samples, except Upsticks, are dissolved in MeOH and H2O. Lipsticks are dissolved in CHCI3, extracted with MeOH by centrifugation, and diluted with MeOH. Filtered before analysis. Sample is mixed with hydromatrix and loaded into the SEE cell. The extracts are collected in EtOH and analysed... 

After dissolving the sample in a beaker, remove any solid impurities by filtering a portion of the solution containing the analyte. Collect and discard the first several milliliters of solution before collecting a sample of approximately 5 mL for further analysis. 

In preparing the sample for analysis the initial solution is filtered. Why is it not necessary to collect the entire filtrate before proceeding ... 

After heating to 50 °C in a water bath, the sample was cooled to below room temperature and filtered. The residue was washed with two 5-mL portions of CCI4, and the combined filtrates were collected in a 25-mL volumetric flask. After adding 2.00 mL of the internal standard solution, the contents of the flask were diluted to volume with CCI4. Analysis of an approximately 2- tL sample gave LfD signals of f3.5 for the terpene hydrate and 24.9 for the camphor. Report the %w/w camphor in the analgesic ointment. 

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