Filter standardization

Property Belt-filter Standard press Vacuum-a ssisted Filter Plates press Cloth Rotary vacuum filter Centrifuge... 

Prepare and filter standard solutions of several of the components shown on the label. The concentrations should be reasonable guesses of what might match what is in the sample. Inject each individually and observe the retention times for each component. Check to see if one of these retention times matches the retention time for a resolved peak from the sample. 

DMSP 3. Algae in culture 4. Filtered standards media algae... 

There are two basic laboratory methods for the preparation of filter standards--dust generation and the liquid suspension technique. Dust generation has a distinct advantage because of the ability to produce atmospheres similar to the workplace which can then be... 

Haartz, Bolyard and Abell ( 3.) used atomic absorption spectrophotometry to check filter standards prepared by the suspension technique Zinc oxide was "spiked" on DM-800 filters and quantitated by AAS and XRD Results from these measurements are shown in Table II, An average deviation of 2 1% was found between the two techniques. Although this data does give a considerable degree of confidence to the use of the suspension procedure for standards preparation, additional data for other analytes is needed for conclusive proof. 

Ceric Sulfate, 0.01 N [3.322 g Ce(S04)2 per 1000 mL] Dissolve 4.2 g of ceric sulfate [Ce(S04)2-4H20] or 5.5 g of the acid sulfate [Ce(HS04)4] in about 500 mL of water containing 28 mL of sulfuric acid, and dilute to 1000 mL. Allow the solution to stand overnight, and filter. Standardize this solution daily as follows Weigh accurately about 275 mg of hydroquinone (CgHg02), dissolve it in sufficient 0.5 N Alcoholic Sulfuric Acid to make 500.0 mL, and mix. To 25.0 mL of this solution add 75 mL of 0.5 N sulfuric acid, 20 mL of water, and 2 drops of Diphenylamine TS. Titrate with the ceric sulfate solution at a rate of about 25 drops per 10 s until an endpoint is reached that persists for 10 s. Perform a blank determination using 100 mL of 0.5 N Alcoholic Sulfuric Acid, 20 mL of water, and 2 drops of Diphenylamine TS, and make any necessary correction. Calculate the normality of the ceric sulfate solution by the formula... 

This figure gives a rough comparison between the different filter standards (filter classes should always be connected to the standard test method). 

Where the powders are not highly potent, final filters on a dust exhaust system should be fine dust filters with a filter classification of F9 according to EN779 filter standards. 

Where harmful substances such as penicillin, hormones, toxic powders and enzymes are manufactured, the final filters on the dust exhaust system should be HEPA filters with at least an H12 classification according to EN1822 filter standards, as appropriate. 

A 2C0mm version of the sonic siever has been developed to take the special screen holders and it is now possible to calibrate the mud screens in less than 5 minutes using the same range of filter standards used for the sand... 

Filter standards used for calibration and method assessment were prepared by adding 2 pL drops of standard solutions with concentration of 0-100 mg L onto blank filters. The solutions were prepared in 100 mL acid washed flasks by dilution of a multi-element standard (Merck CertiPUR, 1,000 mg L ) in 18 MQ cm water obtain from a Milli-Q Gradient system (Milhpore, Bedford, MA) with 7 mL eoneentrated nitric acid (65% HNO3, suprapure grade) and 2 mL of a Rhodamine B dye solution (prepared by dissolution of 0.125 g Rhodamine B... 

Fig. 1 Comparison of drop size, drying and acid content for the preparation of filter standards...

Fig. 2 Calibration of Cr, Cu and Pb performed by LA-ICP-MS analysis of spiked filters. Filters standards were prepared on three different days...

The filtered, standardized, whole aqueous extract of the stem of Tinospora cordifolia was found to stimulate polymorphonuclear (PMN) cell function when incubated in vitro. PMN leucocytes were harvested from the peripheral venous blood of healthy volunteers, patients with obstructive jaundice and patients with tuberculosis. 1 X 10 PMN cells were incubated at 37° C for 1 h with 0.2, 0.4 and 0.8 mg/ml of Tinospora cordifolia (along with the same number of Staphylococcus aureus (in the case of healthy volunteers and patients with obstructive jaundice), or Candida... 

Taking into account dilution of the volatilized fission products before reaching it, the monitoring station has to have the capability of measuring down to 10(xBqm of Ba. The measurement system is called RASA -Radionuclide Aerosol Sampler/Analyser. Detectors of at least 40% relative efficiency are specified to allow the required limit to be achieved in a reasonable time. Direct calibration over the range 88 to 1836 keV using spiked filter standards is used. Monte Carlo and other mathematical methods are not used. The measurement scheme is ... 

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