Filters glass fiber

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. 

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. 

A 200.0-mL sample of water was filtered through a preweighed glass fiber filter. After drying to constant weight at 105 °C, the filter was found to have increased in mass by 48.2 mg. Determine the total suspended solids for the sample in parts per million. 

Dissolved Solids. Dissolved soflds are materials that pass through a glass-fiber filter and remain after evaporation and drying at 180°C. 

Suspended Solids. Suspended soflds are determined by filtering a known volume of water through a glass-fiber filter and weighing the filter before and after filtration. The filter is dried at 105—110°C, and the weight difference is equal to the suspended soflds. 

A gas sample is extracted from the source through a heated sample line, if necessary, and glass fiber filter to a flame ionization analyzer... 

A second sampling program in Southern California sampled for polychlorinated dioxins and polychlorinated dibenzofurans at seven locations (9). Because of the semivolatile nature of these compounds, a tandem sampler was used with a glass fiber filter to collect the particulate-associated compo-... 

When a sampling train requires an unusual combination of sampling media (e.g., glass fiber filter proceeding impinger), the same media/devices should be in line during calibration. 

Wipe sampling involves swiping a dry or wet (use of a solvent or other liquid besides water in eommonplaee) eloth, glass fiber filter paper, or swab over the surfaee of a potentially eontaminated objeet and performing a laboratory analysis. Both the inner and outer surfaees of PPE should be tested to eheek for permeation. Skin ean also be tested using this wipe sampling [1]. 

Experimentally measured dielectrophoretic augmentation factor DAF as a function of air speed and applied voltage for a glass-fiber filter (HP-100, Farr Co.). Cf Fielding, Thompson, Bogardus, and Clark, Dielectrophoretic Filtration of Solid and Liquid Aerosol Particulates, Prepr. 75-32.2, 68th ann. meet.. Air Pollut. Control Assoc., Boston, June 1975. 

Currently available CRMs for Cr(lll)/(VI) species There exist a lyophilized water certified for Cr(III)/Cr(VI) and a binder-free glass fiber filter loaded with welding dust certified for Cr(VI) and total Cr (Vercoutere et al. 1998 Christensen et al. 1999) issued by the BCR. They consist of a set of specimens for single use. There is a need for more CRMs, such as a Cr(VI) in industrial effluents and in river water containing, e.g. humic substances. 

Wang, S.S. Ricauite, G.A. and Peroutka, S.J. [ H]3,4-methylenedioxy-methamphetamine (MDMA) interactions with brain membranes and glass fiber filter paper. Eur J Pharmacol 138 439-443, 1977. 

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. 

Weigh 2.5 or 5 g of crop matrix into a blending vessel. Fortify samples at this point with the appropriate analytical standards. Allow the solvent to evaporate. Add 100 mL of acetone-water (4 1, v/v) and blend the mixture using an Omni mixer equipped with a macro generator for 5 min at 6000-7000 rpm. Filter the sample through a Whatman 934 AFI glass-fiber filter paper on a Buchner funnel/vacuum flask setup. Rinse the blending cup and filter cake with 100 mL of acetone. Transfer the filtrate into a 200-mL TurboVap vessel. 

A water sample is usually analyzed as it is, but is filtered through a glass-fiber filter to remove SS or to analyze both water and SS separately when chemicals adsorbed on SS used to be determined for a special purpose of a study. All filtration apparatus should be washed with the sample water in order to avoid contamination. 

Air is sampled through a glass-fiber filter disk for 6 h at a rate of 2 L min. The filter is placed in a vial containing acetonitrile and the vial is heated at 70 °C for 40 min. After cooling, the vial is ultrasonicated for 15 min. An aliquot of the acetonitrile is filtered and analysed by gas chromatography/mass spectrometry (GC/MS). 

Chromatography columns 100 x 15-mm i.d. with Teflon stopcock Glass-fiber filter (Whatman GF/D, 11-cm)... 

During operation, samples of all flows were taken for suspended solids analysis. These tests were performed by a qualified local analytical laboratory. Procedures for this analysis were as outlined in standard methods.47 Glass fiber filter pads with a particle size retention of 1.2 pm were used. 

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