Standard work

The Supplement B (reference) contains a description of the process to render an automatic construction of mathematical models with the application of electronic computer. The research work of the Institute of the applied mathematics of The Academy of Sciences ( Ukraine) was assumed as a basis for the Supplement. The prepared mathematical model provides the possibility to spare strength and to save money, usually spent for the development of the mathematical models of each separate enterprise. The model provides the possibility to execute the works standard forms and records for the non-destructive inspection in complete correspondence with the requirements of the Standard. 

Prepare a single multicomponent working standard from the stock standards by making appropriate dilutions with methanol. Concentrations in the working standards should be at such a level that a 20- xL sample added to 100 mL of water gives a calibration standard whose response for each trihalomethane is within 25% of that for the samples to be analyzed. 

Determination of the potency of Factor VIII is also difficult. This is normally measured by the abiUty of the sample to correct the clotting time of plasma deficient in Factor VIII. A number of methods and practices have evolved for this purpose (231), but these give very different results, particularly when activation of products may also occur (232). International standards have been used, but further standardization of the analytical method and harmonization of working standards is underway (233,234) under the auspices of the ISTH and the EC. 

Hot Work. The objective of a hot work standard is to prevent fires, explosions, and other causes of injury which might result from workplace ignition sources such as welding (qv), cutting, grinding, and use of electrically powered tools. The OSHA standards have specific requirements (36,94) for fire prevention and protection and a permit system. 

Calibration Cahbration entails the adjustment of a measurement device so that the value from the measurement device agrees with the value from a standard. The International Standards Organization (ISO) has developed a number of standards specifically directed to cahbration of measurement devices. Furthermore, compliance with the ISO 9000 standards requires that the working standard used to cahbrate a measurement device must be traceable to an internationally recognized standard such as those maintained by the National Institute of Standards and Technology (NIST). 

Cahbration of some measurement devices involves comparing the measured value with the value from the working standard. Pressure and differential pressure transmitters are calibrated in this manner. Calibration of analyzers normally involves using the measurement device to analyze a specially prepared sample whose composition is known. These and similar approaches can he applied to most measurement devices. 

HR-ICP-MS EEEMENT-2 (Pinnigan MAT, Germany) equipped with a standard introduction system (quartz water-cooled spray chamber, concentric nebulizer, torch with 1.5 mm i.d. injector and nickel cones) was used for measurements. The following operating conditions were used RP power 1150 W, coolant gas flow rate 16 1 min k auxiliary gas flow rate 0.85 1 min nebulizer gas flow rate 1.2 1 min k Sample uptake rate was 0.8-1 ml min k Measurements were performed with low and middle resolutions. Rh was used as an internal standard. Por calibration working standard solutions were prepared by diluting the multielemental stock solutions CPMS (SPEX, USA) with water to concentration range from 5 ng to 5 p.g I k... 

Do calibrate working standards against calibration standards that have at least an order of accuracy greater than the working standards. 

The inspector s working standard for the surface finish of blast-cleaned steel is now the new British Standard . In the special circumstances where absolute freedom from soluble contaminants such as ferrous sulphate is necessary, the specification should include reference to a test for removal of such residual salts, e.g. the potassium ferricyanide test . The area to be sampled should be wetted with a fine spray of distilled water and the paper held against it. The development of blue spots on the paper indicates the presence of ferrous salts on the surface. 

Standard solutions are not required and in their place the coulomb becomes the primary working standard. 

In flame spectrophotometric measurements we are concerned with solutions having very small concentrations of the element to be determined. It follows that the standard solutions which will be required for the analyses must also contain very small concentrations of the relevant elements, and it is rarely practicable to prepare the standard solutions by weighing out directly the required reference substance. The usual practice therefore is to prepare stock solutions which contain about 1000 ig mL 1 of the required element, and then the working standard solutions are prepared by suitable dilution of the stock solutions. Solutions which contain less than 10 igmL 1 are often found to deteriorate on standing owing to adsorption of the solute on to the walls of glass vessels. Consequently, standard solutions in which the solute concentration is of this order should not be stored for more than 1 to 2 days. 

For procedure (ii) the working standard solutions are prepared as detailed for procedure (i) except that the releasing agent solution is replaced by 10 mL of the stock potassium solution. 

Preparation of the standard solutions. The standard solutions are prepared from a solution of vanadium naphthenate in white spirit which contains about 3 per cent of vanadium. Weigh out accurately about 0.6 g of the vanadium naphthenate into a 100 mL graduated flask and make up to the mark with white spirit this stock solution contains about 180/igmL-1 of vanadium. Dilute portions of this stock solution measured with the aid of a Grade A 50 mL burette to obtain a series of working standards containing from 10-40/igmL-1 of vanadium. 

Arsenic standards. Prepare a 1 mgL-1 working standard solution from a 1000 mg L-1 SpectrosoL solution of arsenic trichloride in a 4M hydrochloric acid. 

To obtain the calibration standards, take aliquots ranging from 50 /xL to 300 juL As, from the working standard solution, using an Eppendorf micropipette. Add the appropriate microlitre quantities to the reaction vessel of the vapour generation system, together with 10 mL of hydrochloric acid (AM), delivered from a calibrated dispenser. 

Full-service programs require that the water treatment account representative be part of a larger sales and services and technical support team. When such a team subscribes to quality work standards and environmentally responsible practices, they present a formidable taskforce and a valuable partner to their customers. 

In contrast, the treatment of industrial steam generation plants is usually more difficult. There is a need to conform to a good working standard and to produce quality waterside conditions for a long period of time without serious upsets, as the systems are always very dynamic and operating conditions can continually vary. This is especially the case with those facilities whose manufacturing operations may employ some form of on-off cycle or up-down batching process, rather than a steady-state, continuous production stream. 

In a multi-year, multi-laboratory situation it is unlikely that the amount of primary standard (PS) will suffice to cover all requests. The next best thing is to calibrate a larger amount of lower-quality secondary standard (SS) against the PS, and to repeat the calibration at specified intervals until both the PS and the SS have been consumed. In this way, consistency can be upheld until a new lot of PS has been prepared and cross-validated against the previous one. In practice, a working standard will be locally calibrated against the SS and be used for the daily method calibration runs. (See Section 4.32.)... 

A secondary chemical reference substance is a substance whose characteristics are assigned and/or calibrated by comparison with a primary chemical reference substance. The extent of characterization and testing of a secondary chemical reference substance may be less extensive than for a primary chemical reference substance. This definition may apply to some substances termed Working Standards . 

Laboratory Accreditation and Quality Systems" Together these make laboratory managers look for added security in assuring data quality and thus invoke a desire in them to fall back on the best available standard. The result is that a CRM is often used instead of a working standard. This is a tendency that is supported and encouraged by some RM providers but discouraged by others. 

Nothing Else Available When there is no commercial working standard, and there is a CRM available, many scientists will not bother to spend the time and effort required to characterize an in-house standard. 

Stock solutions of approximately 1 mg mL were prepared by dissolving the appropriate amounts of the analytical standards in acetonitrile. Working standard solutions for fortification were prepared in volumetric flasks by appropriate dilutions of the stock solutions for each analyte or combination of analytes. During analysis, SCA is converted to DMS and HMS is derivatized therefore, the analytical standard solutions for quantitation and instrument calibration contained sulfentrazone, DMS and derivatized HMS. A measured volume of a standard solution containing sulfentrazone, DMS and HMS (prepared from stock solutions) was derivatized simultaneously with the samples. 

Stock standard solution containing 1 mg mL mancozeb. Dissolve about 13.5 mg of mancozeb (taking into consideration the purity of the standard, which is about 74%) in 10 mL of 10% EDTA solution. Prepare this stock solution daily. Prepare working standard solutions by diluting appropriate volumes of the stock solution with 10% EDTA in order to obtain concentrations between 2.5 and 50 qg mL mancozeb. 

Procedure. Five aliquots of the triazole stock solution of 5, 10, 15, 20, and 25 ml. are introduced into 50-ml. volumetric flasks. Each aliquot is diluted to 50 ml. with hexane, making working standards equivalent to 10, 20, 30, 40, and 50 micrograms of triazole per ml., respectively. Using a volumetric pipet, 1 ml. of each working standard is... 

The current official FDA Chlortetracycline Working Standard is chlortetracycline hydrochloride, Lot //501-632B-95-1 (9/29/53), obtained from Lederle, which markets the antibiotic under the proprietary name Aureomycin. The current working standard has an assigned potency of 1000 yg/mg (the term yg applied to chlortetracycline means the chlortetracycline activity (potency) contained in 1 yg of the FDA Chlortetracycline Master Standard (Lot 990-107-141-1), which is also chlortetracycline hydrochloride). 

The Working Standard is stored in lots of 250 mg at -20°C, protected from light and moisture, at the National Center for Antibiotics Analysis, Washington, DCi... 

The X-ray diffraction pattern of the FDA Working Standard has been determined. It demonstrates crystalline structure the data are listed in Table 2 (16). 

The CTC-HC1 FDA Working Standard gives a yellow fluorescence under longwave ultraviolet (UV) light (375 nm) (35). The excitation (324 and 357 nm) and emission (443 nm) spectra of this standard dissolved in 0.05N NaOH (11.4 mg/50... 

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