Filter glass-fibre

Hydrazine in air Lab method using sampling either onto acid-coated glass-fibre filters followed by solvent desorption or into specially constructed impingers. Linal analysis by derivatization and high performance liquid chromatography 86... 

Impinger preceded by filter Glass fibre filter Impinger or fritted bubbler Miscellaneous sampler (dosimeter etc.)... 

Other applications of filters include sterilization of venting or displacement air in tissue and microbiological culture (carbon filters and hydrophobic membrane filters) decontamination of air in mechanical ventilators (glass fibre filters) treatment of exhausted air ftom microbiological safety cabinets (HEPA filters) and the clarification and sterilization of medical gases (glass wool depth filters and hydrophobic membrane filters). 

Cultures from different times of growth were collected. Culture fluids were cleared by passing through glass fibre filter. After dialysis for 16-18 h against distilled water at 5°C, filtrates were assayed for enzyme activities and proteins. 

Preparation of enzyme. Culture fluids of three days on glucose 0.5% (w/v) and then four days on pectin 0.5% (w/v), cleared by passing through glass fibre filter, were used for the purification of PNL. A small quantity was remainder, dialyzed, and assayed for enzyme actitity and the remained was precipitated. 

If a dust filter is required, it should be in front of the olfactometer and not in front of the sampler. Experiments should be carried out to demonstrate that the properties of the odour have not been changed by the filter. Glass fibre filters are in use in Germany (LIS, Essen) and in the Netherlands (MT/TNO, Apeldoom). 

Alfheim, I., A. Jebens, and S. Johansen, Sampling Ambient Air for Mutagenicity Testing by High-Volume Filtration on Glass-Fibre Filters and on XAD-2, Environ. Int., 11, 111-118 (1985). 

Air particulates are usually dissolved before analysis, but again, solid samples (e.g. on glass-fibre filters) have been analysed directly in furnaces. 

V-Nitrosodiethanolamine can be determined in air and bulk process samples. Air samples are collected on glass fibre filters, extracted with 2-propanol and analysed by gas chromatography with thermal energy analyser detection. The limit of detection is 200 ng per sample (0.42 pg/m ). Bulk samples can be screened for 7V-nitrosodiethanol-amine by high-performance liquid chromatography (HPLC) with ultraviolet detection (Occupational Safety and Health Administration, 1990). 

Timolol concentration in tear fluid samples was measured in the same way, but 200 pi of the diluted tear fluid in phosphate buffer were used instead of 180 pi plasma. After incubation, bound and free radioligand were separated by vacuum filtration through Whatman GF/F glass fibre filters. Filters were washed three times with 10 ml ice-cold 310 mOsm phosphate buffer, dried and counted for retained radioactivity in 5 ml of Lipoluma-Lumasolve-water (10 1 0.2) mixture using... 

The precipitates were separated by glass fibre filter, washed by ethanol and air-dried. In some cases X-ray diffraction (by Philips 3710) for polymorphism and SEM analysis (by Philips XL 30 ESEM) for habit determination were made. 

The May Pack has been used world-wide to characterise radioiodine. In some applications, glass fibre-filters have replaced membrane filters and copper or silver gauzes have been used to trap elemental iodine. The separation of iodine species in the May Pack is at best qualitative. Some inorganic iodine vapour may be adsorbed on the particulate filter. Conversely, iodine adsorbed on particles, and trapped on the particulate filter, may be desorbed during extended periods of sampling. 

Sherwood Stevens (1965) examined glass-fibre filters from personal air samplers worn by workers in the Radiochemical Laboratories at Harwell. The filters were mounted in an Araldite mixture which rendered them transparent and were covered by autoradiographic stripping film. After exposure and development, the samples were viewed with a high-power optical microscope. Particles were sized, and their activity determined from the number of alpha tracks coming from them. An extremely wide range of particle sizes, 0.2 to 90 m, was found. The smaller particles were plutonium compounds or alloys, and the larger were inert particles with one or more small Pu particles attached to them. An example of the latter is shown in Fig. 5.3. 

PH adjustment / filtration The pH adjustment/filtration test evaluates the effect of pH change and filtration on the toxicity of substances associated with filterable material, focusing on irreversible chemical reactions. Effluent samples, at pH 3, 11 and / are filtered (using positive pressure) through a glass fibre filter (1.0 p. pore size). The pH of each filtered sample is re-adjusted to pH / prior to testing. 

Chlorophyll concentrations were estimated from 40 ml subsamples following Suzuki and Ishimaru (1990). Samples were filtered on Whatman GF/F glass-fibre filters (pore size 0.45 pm). Chlorophyllous pigments were extracted by direct immersion of the filters in 5 ml of N,N-dimethylformamide, and actual extractions were made in the dark at 20°C. Concentrations of chlorophyll a in the extracts were determined following Strickland and Parsons (1972) using a Turner 450 fluorometer previously calibrated with chlorophyll a extracted from Anacystis nidulans (Sigma Chemicals, St Louis). 

Using one IJhatman GFA 13 cm glass fibre filter per liter of brine. 

A major aliquot of a peak fraction (90%) was subjected to automated Edman degradation (model 477, Applied Biosystems). Typically, fractions of ca. 60 pi were applied to a polybrene-coated glass fibre filter and sequenced. 

Glass fibre filters and membrane filters (0 50 mm) were spiked with weighed amounts of an Am or Cs standard solution. The spiking procedure was carried out by immersing the filter in a small volume of the standard solution and evaporation of the solvent. 

In the NVN 5636 intercomparison, six laboratories analyzed glass-fibre filters and membrane-filters for gross alpha and gross beta activity (see table 3 and table 4). The result for one laboratory was rejected as an outlier. 

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