Filter papers ashless

Filter the pulp sample (fibre-water suspension) through a Schleicher Schuell Black ribbon no 5891 ashless filter paper with water suction. Immerse the calibrated Ca(II)-ISE and the Ag/AgCl/3M KC1 reference electrode in the filtrate and record the potential (E (mV)) until a stable reading ( + 0.5 mV) is obtained. Calculate the Ca(II) activity of the pulp sample by using the calibration plot. 

A 50 mg sample of each ground fabric was introduced into a 50 mL Erlenmeyer flask, and 20-30 mL of deionized/distilled water was added. After approximately 15 minutes, each solution was filtered through ashless filter paper into a 100 mL volumetric flask. A 2 mL aliquot of Nessler s Reagent (APHA, Fisher Scientific Company) was... 

Sample Solution Accurately weigh 1 g of a solid-mbber sample, wrap it tightly in ashless filter paper, and place it in a tared platinum cmcible. Heat in an oven at 100° for 15 min, and then transfer to a muffle furnace programmed to reach 500° within 1 to 3 h after introduction of the sample. Remove the crucible from the furnace 15 to 20 min after 500° has been reached, and cool in a desiccator. Quantitatively transfer the contents of the cmcible to a 100-mL volumetric flask, using 1 mL of hydrochloric acid and water, dilute to volume with water, and mix. 

Place the uncovered beaker on a hot plate, and heat the contents vigorously until the center of the bottom of the beaker becomes clear. Remove the beaker, and cool to room temperature. Add 5 mL of hydrochloric acid, and heat again until white fumes evolve. After cooling, dilute the solution to approximately 100 mL with water, adjust to pH 6 0.2 with 10% sodium hydroxide, and heat the solution to boiling. Add 15 mL of 10% barium chloride solution, and leave the solution overnight in a fresh beaker in a steam bath at 90° to 95°. Filter through ashless filter paper (Whatman No. 42, or equivalent), and wash the precipitate with 200 mL of warm water. Transfer the paper and precipitate to a tared crucible. Heat the crucible slowly on a Bunsen burner to expel moisture. Place the crucible and contents in a muffle furnace at 850° for 1 h. Let the crucible cool in a desiccator, and then weigh the residue to the nearest 0.0001 g. Calculate the percent of sulfonate sulfur by the formula... 

Sample Solution Fill a 100-mL porcelain crucible halffull of ashless filter paper pulp. Place 2 g of the finished catalyst, in droplet or flake form and accurately weighed, on top of the paper pulp. Transfer the crucible to a muffle furnace set at room temperature, and slowly raise the temperature to 650° so that the stearine melts into the paper, and the organic mass bums and chars slowly. Continue heating at 650° for 2 h or until the carbon is burned off. Cool, add 20 mL of hydrochloric acid, quantitatively transfer the solution or suspension into a 400-mL beaker, and carefully evaporate to dryness on a steam bath. Cool, add 20 mL of hydrochloric acid, warm to aid dissolution (catalysts containing silica will not dissolve completely), transfer into a 500-mL volumetric flask, dilute to volume with water, and mix. Allow any solids to settle, pipet a clear, 50-mL aliquot into a 400-mL beaker, and dilute to 250 mL with water. (If there is suspended matter in the volumetric flask, filter a portion through a dry, medium-speed filter paper into a dry receiver, and pipet from the receiver.)... 

Unless otherwise directed, accurately weigh about 3 g of the sample in a tared crucible, ignite it at a low temperature (about 550°), not to exceed a very dull redness, until it is free from carbon, cool it in a desiccator, and weigh. If a carbon-free ash is not obtained, wet the charred mass with hot water, collect the insoluble residue on an ashless filter paper, and ignite the residue and filter paper until the ash is white or nearly so. Finally, add the filtrate, evaporate it to dryness, and heat the whole to a dull redness. If a carbon-free ash is still not obtained, cool the crucible, add 15 mL of ethanol, break up the ash with a glass rod, then burn off the ethanol, again heat the whole to a dull redness, cool it in a desiccator, and weigh. 

An alternative method for carrying out this test is to soak some ashless filter paper in aluminium salt solution, add a drop or two of cobalt nitrate solution and then to ignite the filter paper in a crucible the residue is coloured blue. 

An alternative method is to soak a piece of ashless filter paper in the zinc salt solution, add 1 drop cobalt nitrate solution and to ignite in a crucible or in a coil of platinum wire. The residue is coloured green. 

Thermal Degradation. Whatman No. 42 ashless filter paper has a basis weight of 92 g/cm2, an a-cellulose content of 98%, and a solubility in hot 1%... 

The furnace was tested for its recovery using aliquots of tritiated th)nnidine tracer and a C-14 carbonate tracer (Amersham QSA, Harwell). Aliquots of both tracers were added on to a Whatman ashless filter paper and placed in one of the furnace work-tube. The optimized 4 hour protocol was used for the recovery test run. Wallac Quantulus 1220 Liquid Scintillation Counters, calibrated using certified H-3 and C-14 standards, were used for measurements (Table 2 shows relevant technical information for the Quantulus counters and the resulting yields of the test sample runs). 

Ashless filter paper Paper produced from cellulose fibers that have been treated to eliminate inorganic species, thus leaving no residue when ashed. 

Ashless filter paper is generally used for quantitative work in which the paper is ignited away and leaves a precipitate suitable for weighing (see Chapter 10). There are various grades of filter papers for different types of precipitates. These are listed in Table 2.6 for Whatman (www.whatman.plc.uk > and for Schliecher and Schuell twww.s-und-s.de/english-index.htmD papers. 

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