Glass fiber filter sampling volume

Total airborne particulates are determined using a high-volume air sampler equipped with either cellulose fiber or glass fiber filters. Samples taken from urban environments require approximately 1 h of sampling time, but samples from rural environments require substantially longer times. 

Nonvolatile compounds are normally present either as solid particulates or bound to solid particulates. Samples are collected by pulling large volumes of gas through a filtering unit where the particulates are collected on glass fiber filters. 

Particulate gravimetry is commonly encountered in the environmental analysis of water, air, and soil samples. The analysis for suspended solids in water samples, for example, is accomplished by filtering an appropriate volume of a well-mixed sample through a glass fiber filter and drying the filter to constant weight at 103-105 °C. 

Plant material. Weigh 25 g of the chopped and frozen sample into a blender jar. To check recoveries, spike the fortification samples with the appropriate volume of metabolite standard at this point. Add 200 mL of acetonitrile-water (4 1, v/v) to the jar, and blend the sample at medium speed for 5 min. Filter the extract through a Buchner funnel fitted with a glass-fiber filter pad into a 500-mL round-bottom flask containing 10 drops of Antifoam B and 3 mL of 10% aqueous Igepal CO-660 (nonionic surfactant). The flask is connected to the Buchner funnel by means of an adapter suitable for applying vacuum to the system. 

HPLC methods with fluorescence detection have also been developed for the determination of nitro-policyclic aromatic hydrocarbons (PAHs) (among which 9-nitroanthracene and 1-nitronaph-thalene) [238] in atmosphere. Samples have been collected in a standard high-volume sampler with a Teflon-coated glass fiber filter, and the Soxhlet extraction was performed with dichloromethane as the solvent. RP HPLC/UV techniques are used for the determination of aldehydes, ketones, and carbonylic compounds after derivatization with DNPH [239],... 

Thrane, K. E., and A. Mikalsen, High-Volume Sampling of Airborne Polycyclic Aromatic Hydrocarbons Using Glass Fiber Filters and Polyurethane Foam, Atmos. Environ., 15, 909-918 (1981). 

Fibrous mat type filters include the frequently used paper (cellulose) fiber filter, for example, the Whatman paper filter, and glass fiber filters. A common fibrous mat filter used for sample collection and air cleaning is known as the HEPA filter (/zigh efficiency particulate air filter) and is made of a combination of cellulose and mineral fibers. A widely used type of fibrous mat filter is the high-volume filter, commonly referred to as Hi-Vol, shown in Fig. 11.56. A modification of the Hi-Vol filter to increase the total air flow allows the collection of sufficient particulate matter in relatively short time periods (e.g., 2 h) to cany out chemical analysis this is important for studies of the diurnal variation of various chemical components of the aerosol as well as for minimizing sampling artifacts (Fitz el ai, 1983). 

In some designs, a glass fiber filter is supported above the extraction disc to prefilter samples containing particulates without clogging the extraction disc. Because of the rigid disc design, frits to support the extraction disc are not necessary. The polyethylene frits used in conventional SPEi columns may be a source of contamination (90) and have a large surface area and void volume. 

Another problem encountered was the impurity content of the filter paper used in the high volume samplers to collect the particulate samples. The conventional filter material used by EPA was glass fiber filter media. However, this was not compatible with INAA because of its high and varied impurity content. Discussions with K. Rahn of the Ford Reactor at the University of Michigan revealed that Whatman-41 filter paper was the most desirable medium for use with INAA (see Ref. 2). Our analyses showed Whatman-41 to be very low in impurities with consistent impurity levels from batch to batch. Average impurity levels, based on 12 batch analyses, are shown in Table III. Although the levels for calcium, chlorine, sodium, aluminum, and iron appear large, they rarely affected elemental levels found in filtered particulates. Impurity levels did not vary more than 25% from the mean. 

Analogous to sampling TIN with the filter pack method, sampling with a quartz- or glass-fiber filter followed by a sorbent can provide a relatively accurate measure of the total (i.e., vapor plus particle phase) concentration of specific PAH compounds. Such methodologies were reviewed by Lee et al. (73). Selection of a sorption medium for collection of vapor-phase PAHs is influenced by air-flow resistance, collection efficiency, breakthrough volume, the effort required to purify the medium for use, and the efficiency with which the PAH can be recovered from the sorbent. 

Surface Interactions. Loss of strong acid content of atmospheric aerosols was observed and attributed to reaction with basic sites in the glass or cellulose filter matrices commonly used for high-volume sampling of atmospheric aerosols (46, 50). These filter materials, and glass fiber filters of... 

Air drawn through a glass fiber filter and then through a sorbent tube containing silica gel (520 mg/260 mg), ethylene glycol desorbed out from silica gel with 2% isopropanol in water (on 5-min standing) the analyte in eluant determined by GC-FID (NIOSH Method 5500, 1984) recommended air flow rate 0.2 L/min sample volume 30 L. 

Air drawn through a 37-mm glass fiber filter strychnine deposited on the filter, desorbed with 5 mL mobile phase for HPLC-UV detection at 254 mm (NIOSH method 5016,1985) recommended air flow rate 2 L/min sample volume 500 L. 

Air samples for airborne portions may be taken with high volume air samples 0.67-0.85 m3 (20-30 ft /min.) through a glass fiber filter backed up with a resin type (Rohm and Haas XAD) absorbing column or liquid bubbler for gas phase trapping where desired. Any type application may be monitored downwind with these type of collectors at ground level, or vertical tower collection can be provided for Impacted drops or for those drawn into air samplers. 

Air (CDDs) Collection of sample onto glass fiber filter/polyurethane foam cartridge addition of internal standard Soxhlet extraction with toluene volume reduction clean-up and fractionation on Florisil , elutiion with toluene/diethylether, evaporation and redissollution in cyclohexane clean-up on modified silica gel using HPLC and hexane/diethyl ether volume reduction HRGC/LRMS (EI/SIM) HRGC/LRMS (NCI/SIM) 0.1-1 pg/m3 0.2-3 pg/inj (0.01-0.1 pg/m3) 80-122 86-102 Oehme et al. 1986... 

In the laboratory, aerosol samples were individually cut from the filter-tape roll and extracted on a 47-mm filter holder (Millipore) with 200 mL of distilled deionized water maintained at 50-60 °C. The leachates were analyzed for sodium content by flame atomic absorption with a Perkin-Elmer Model 373 spectrophotometer. The soluble sodium was assumed to be derived only from sea salt. Estimates of total sea salt in each sample were obtained by multiplying the sodium value by 3.25, which is the salinity-to-sodium ratio in bulk seawater (12). The sodium content of the 5-cm diameter, glass-fiber filter blanks averaged 18 /xg 12% (20 samples). Based on an average sample volume of 27 m, the background salt level produced by the sodium blank in each filter would be equivalent to 2.2 /xg/m. ... 

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