Reference standards supply

The water sample is obtained from the Environmental Laboratory Approval Program. We have used ICP-AES multi-element Reference Standard supplied by E. Merck with Lot. No 0C030033 for standard calibration. These standards have certified data obtained from NIST as third-generation traceability, assuring reasonable accuracy in the estimations (Certificate of Analysis, Certipur - Reference Material 11355 ICP multielement standad IV made from NIST standards reference materials, Lot No. 0C030033. Dr. Harald Untenecker, Central Analytical Laboratory, Merck). An echello-gram showing all the elements is attached. 

Materials. Aldicarb standards were obtained from the United States Environmental Protection Agency (USEPA), Quality Assurance Section and from Union Carbide Corporation. Crystalline samples of carbofuran and 3-hydroxycarbofuran were supplied by the Agricultural Chemical Group of FMC Corporation. Reference standards of methomyl (99% pure) and oxamyl (99% pure) were obtained from USEPA. HPLC grade methanol was purchased from Burdick and Jackson, Inc. Methylene chloride used for bulk extractions of the carbamate pesticides in solution was recovered, distilled and reused. Analytical reagent grade chemicals and solvents were used in all experiments. Doubly distilled deionized water was used for solution rate studies. Deionized distilled water (DDW) was used for dilutions in reactive ion exchange experim ts., , ... 

Commercially supplied reference standards obtained from a reputable commercial source... 

Power sources based on the zinc-mercuric oxide system are particularly suited to a wide range of applications, mainly concerned with miniature portable electronic equipment, where a relatively constant voltage is required throughout long discharge periods. In addition, such cells are used as voltage reference standards in regulated power supplies, potentiometers, chart... 

The material from an appropriate bulk supply of the matrix material is weighed into a suitable container and homogenised. Where appropriate, portions of the matrix material are tested for the analytes of interest and for possible interferences. Pesticide and environmental test samples are usually prepared by spiking known amounts of substances of specified chemical purity into the bulk sample matrix. The spiking process is witnessed and cross-checked by a second scientist and full records of the process and of reference standard solutions used are maintained so that they can be verified if required. 

More than 220 producers of CRMs throughout the world produce today 12,000 20,000 materials with dif ferent matrixes, analytes and properties [4]. However, many testing (analytical) laboratories cannot find suitable CRMs in the market and develop in-house reference materials (IHRMs) themselves. Often IHRMs are developed in a laboratory to conserve the corresponding expensive CRMs. For example, a pharmaceutical company Chemagis Ltd. produces 30 active pharmaceutical ingredients steroids, benzodiazepines, antihistamines, hipolipidaemics, blood flow reactants, etc. Only for a few of them Mo-metasone Furoate, Fluticasone Propionate and Dobutamine Hydrochloride are of fi-cial reference standards for assay supplied by US, British and European Pharmacopoeias with prices of about 180 per unit (50 200 mg). Thus, to support its customers Chemagis is forced to develop IHRMs for assay as well as for impurities and related substances of each produced compound. Therefore, certification of such IHRMs that leads to traceable values is very important. 

Method robustness was established to show assay consistency with various supplies of the reference standards and two other critical reagents ... 

Thermal analysis is a useful tool in the quality control of many incoming routine materials, which can be tested against a reference standard developed internally by analysing a large number of samples of known performance criteria to ensure that the quality of supplies is maintained. Solid elastomers can be identified by glass transition temperature (Tg) [70]. The rubber industry uses thousands of different raw materials, and this number is steadily increasing. These materials are listed in [172]. 

The development and standardization of reliable test procedures requires an ample supply of well-characterized reference materials. These samples are used for round-robin tests by participating laboratories in the method development. A reliable set of reference materials are available from the National Bureau of Standards. These special reference materials are described by Haines in this symposium series. The Bureau has packaged the materials in an appropriate size and secure container. Producer and user laboratories have these reference materials available to cross-check results and resolve differences in specification analyses. These reference standards are available at a reasonable cost. 

In support of its program for public standards for drugs, the USPC supplies the Reference Standards required by the monograph standards, tests, and assays of both the USP and the NF. Biologic assays in the USP were the first to require use of reference materials. Authoritative sources of these were needed, and the first were adopted in 1926. As an index of the growth of analytical science, 45 were needed in 1950 for the USP and NF and 438 in 1980. As of 2000, there are 1400. 

Reference Standard A reference standard is broadly defined as certified material or substance, supplied by a certifying body, which exhibits one or more properties that are sufficiently well established (and assigned) that it may be used for calibration of an apparatus, assessment of a measurement method, and assigning values to materials. Reference standards in pharmaceutical sciences generally fall within three categories analytical reference standards, working standards, and authentic materials. 

The drug development team must ensure that reference standards will be available to support the launch of a newly approved product once FDA approval is obtained. The quality control function is typically separate from the analytical development function in most firms, so a high level of cooperation and communication are critical. As launch approaches, the drug development team must work closely with the commercial manufacturing quality control unit to coordinate the supply of reference standards to the firm s compound distribution system. It is useful to involve marketing forecasts to predict the approximate amounts of reference standards—based on projected batches—that will be necessary to support a worldwide launch. 

Levothyroxine is another example of an active pharmaceutical ingredient with relatively poor stability that is available as a USP analytical reference standard in the free acid form, while the drug is formulated as the sodium salt in most commercial preparations.84 Levothyroxine is prone to extensive photochemical decomposition85 that is thought to be exacerbated by the facile ionization of the phenolic hydroxyl group.86 Supply of the USP analytical reference standard as the free acid provides a more stable form through suppression of the ionization of the phenolic hydroxyl. 

Aqueous standards are prepared from 1000 ppm E. Merck standard reference material supplied with NIST traceability. The standards are made up using 18 Mfl Milli-Q water with 1% v/v high quality nitric acid 65%-Fluka Chemie. 

Whether the material is called an analytical reference standard, a working standard, or an authentic sample, material must eventually be supplied (preferably solid form) to the analyst to quantify impurities. Only with a sufficiently pure sample can the analyst accurately measure the response of an impurity in an assay. The impurity s molar absorptivity in a UV detector may differ widely from that of other components, resulting in either an underestimate or overestimate of its presence by HPLC. An impurity s response to developing sprays used in TLC is best quantified by comparison to known concentrations. 

The selection materials and samples to be used in the transfer should be described in detail. In general, one does not choose GMP released materials for transfer activities because the result of not meeting the predetermined acceptance criteria could be an out-of-specification (OOS) investigation. The identity and lot numbers of specific batches should be given. If possible, certificates of analysis for all samples, including reference standards, should be supplied. The instrumentation should be... 

At a minimum, documentation of the characterization and stability of a standard, such as a certificate of analysis (Co A) and/or a certificate of stability (CoS), is typically available from the suppliers. The certificate should be obtained and recorded. The quantity of reference standard is typically limited in commercial kits designed for research use, and it is not uncommon that the reference material values may differ substantially between lots and manufacturers [16]. Novel biomarkers rarely have established gold standards against which their potency and abundance can be calibrated. A comparison of available sources can be useful, and when validating an assay for advanced applications it is desirable to plan ahead to obtain and reserve a sufficient supply of the same reference material. The example in Fig. 6.5 compares three reference standard curves, each prepared from a concentrated stock solution from a commercial supplier, an in-house reference standard, and a commercial kit, respectively. The instrument responses (optical density, OD) were highest with the standard from the commercial stock, the lowest with the kit, while the in-house reference standard response was intermediate. In this case, either the same commercial stock or the in-house reference standard can be used throughout the clinical study. 

In addition to commercial producers, the National Institute of Standards and Technology supplies primary standard chemicals. NIST Special Publication 260 catalogs standard reference materials. (See http //ts.nist.gov/ts/htdocs/23Q/232/232.htm for information on the SRM program and lists of reference standards.) Reference standards are complex materials, such as alloys that have been carefully analyzed for the ingredients and are used to check or calibrate an analytical procedure. 

Domoic acid by ELISA (Kleivdal et al., 2006). ° Sixteen participating labs, 10 reporting acceptable data. Eleven materials comprising scallop, mussel, and oyster tissues fortified at two or three levels plus a blank. The fortified materials were supplied as split-level duplicates. A certihed reference standard for DA (NRC, Halifax) was provided as part of the... 

Characterization data—Full characterization data should be supplied for the primary reference standard, including the results from analytical testing and spectral characterization. The assigned purity of the reference standard should be clearly designated. 

In addition to laboratoiy glassware and equipment necessary fOT cleanup of the extract, traditional pesticide residue methods require expensive chromatogrsqihic instrumentation for identification and quantitation of residues. EIA methods require minimal amounts of glassware, disposable plasticware, or other supplies. Quantitative EIAs often make use of 96-well microtiter plates fOT multiple simultaneous assays of about a dozen extracts and associated reference standard. Major equipment consists of a plate reader, which automatically measures the absorbance of each well. Plate readers can be used alone or in conjunction with a personal computer, which can correlate replicate measurements, construct the calibration curve, calculate results, and provide a complete statistical analysis. Such an EIA workstation can be obtained for roughly half the cost of the GC or HPLC system typically used for pesticide residue analysis. 

The Gas Research Institute (GRI) also became aware of industry interest in new reference standard mixtures certified by an independent agency. As a result, in August of 1984, GRI initiated the present program at IGT with the ultimate goal of supplying the gas industry with a series of NBS traceable calibration gases. 

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