Reference standard analytical

APPENDIX 18-7 STANDARD REFERENCE SOLUTIONS AND INSTRUMENT CALIBRATION 

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Reasonable grounds in support of tolerance petition Analytical reference standard(s)... 

EPA. 1984. Analytical reference standards and supplemental data The pesticides and industrial chemicals repository. EPA, Las Vegas, NV. EPA 600/4-84-082. October 1984. 

OPPTS 860.1560 Reasonable Grounds in Support of the Petition OPPTS 860.1650 Submittal of Analytical Reference Standards OPPTS 860.1850 Confined Accumulation in Rotational Crops OPPTS 860.1900 Field Accumulation in Rotational Crops. 

It is largely without debate that the term "reference substance" includes those chemical and biological materials that are used as standards in a study (i.e., those materials used for response comparison purposes, such as analytical reference standards). Normally, one thinks of reference substances as just referring to specimen (sometimes referred to as "matrix samples") analyses, but the characterization of test, control, and reference substances (see... 

The purity of the reference standard used to prepare spiked samples can affect the study data. For this reason, an analytical reference standard of known identity and purity should be used to prepare solutions of known concentrations. If possible, the reference standard should be identical to the analyte. When this is not possible, an established chemical form (free base or acid, salt, or ester) of known purity can be used. Three types of reference standards are generally used ... 

Thompson, J. F. Watts, R. R. "Analytical Reference Standards and Supplemental Data for Pesticides and Other Organic Compounds", EPA publication 60019-78-012, 1978. 

Custodian of analytical reference standards, receiving and cataloging incoming standards, discarding expired standards. 

On the other hand, the analyte or analyte reference standard may contribute to the response of an internal standard either due to impurity or because of natural abundance of stable isotopes (say m %). Therefore, the concentration of the internal standard must not be too low. Otherwise, the contribution from the analyte or its reference standard would be significant, e.g., more than 5 % of IS concentration or response [16], and linearity and accuracy could be greatly affected. Accordingly, a minimum IS concentration could be obtained based on the ULOQ for the analyte. For this reason, a high IS concentration is preferred. 

Were analytical reference standards analyzed concurrently and... 

An analytical reference standard or working standard usually derived from a production batch is normally established as the comparative standard for routine analyses of the bulk drug substance for release purposes. It should be characterized against the primary standard. 

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. 

Analytical Reference Standard An analytical reference standard (ARS), also known as primary standard or gold standard, is defined as a batch of drug substance, whose purity is independently established and accepted without reference to other standards. The ARS is the benchmark against... 

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. 

Analytical Reference Standards and Supplemental Data," Environmental Protection Agency, 1984. 

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. 

Rat toxicity values were obtained from EPA publication-600/2-81-011, "Analytic Reference Standards and Supplemental Data for Pesticides and Other Organic Compounds". The rat oral LDso for the racemic mixture of cypermethrin is 251 mg/kg. The mouse intracerebral LDso values are 0.6 jug/g brain weight for the 1 ff,cis,(XS and 1.6 for the 1 ff> trans, -S isomers (15). 

JK Baker, CW Myers. One-dimensional and two-dimensional I I- and 13C-nuclear magnetic resonance (NMR) analysis of vitamin E raw materials or analytical reference standards. Pharm Res 8 763-770, 1991. 

Reagents and Standard Compounds. Analytical reference standards of dicamba, 2,4-D, atrazine, diazinon, pentachlorophenol, and lindane were obtained from the U.S. EPA Pesticides and Industrial Chemicals Repository (HD-8), Research Triangle Park, NC 27711. Stock solutions were prepared in pesticide grade methanol or acetone (Baker resi-analyzed) and stored at -10°C. 

Chemicals, Analytical reference standards for Aroclor 1254 and 1260 were provided by the U. S. EPA (Research Triangle Park, NC). Solvents were commercially available, pesticide grade and were used as received. 

In terms of residues in food, stability is an important parameter as it relates to (1) residues in biological matrices during storage, (2) analytical reference standards, (3) analytes in specified solvents, (4) samples prepared for residue analysis in an interrupted assay run such as might occur with the breakdown of an analytical instrument, and... 

Information on the analytical reference standard Description of the container/closure system Stability data... 

Information on the analytical reference standard—Once a suitable reference standard for the API is established, appropriate information on its manufacture and results from characterization studies should be included in the investigational... 

Chemicals. Pesticides were analytical reference standards provided by the U.S. Environmental Protection Agency Pesticides and Industrial Chemicals Repository (Research Triangle Park, NC). Acetonitrile and toluene (pesticide grade) and other chemicals... 

In many instances, the analytical reference standard will be readily available from one or more commercial sources but this is not always the case. Certified reference materials (Section 2.2.2, not natural matrix CRMs but calibration solutions that are solutions of a reference standard at a certified concentration in a clean solvent) must be prepared and characterized in accordance with the strict guidelines in ISO Guide 34-2000 (ILAC 2000). The reference standard may also be supplied by the chent and this is often the case when working with proprietary compounds in development. If neither of these two options exist, the standard must be synthesized or in some instances extracted from a natural product or commercial formulation and then purified. The requirements for obtaining a certificate of analysis (Section 9.4.4c) or other documentation that establishes the identity and purity of the analyte are discussed in Section 2.2.2 and also below in 9.4.4c, but the amount of standard available is also an important factor in terms of formulating a strategy for the... 

For studies of more than four weeks in experimental duration, a reserve sample of each batch of the test, reference (analytical reference standard) and control substance must be retained. As this archive sample may be retained by either the sponsor or the contract facility, the responsibility should be addressed in the protocol. Additionally, a sample of the chemical should be collected prior to each application and immediately frozen for possible analysis for "storage stability of the test, reference and control substance at the test site". If the sponsor s storage stability data are inclusive of the storage conditions recorded at the test site, the GLP requirement will have been met and the above storage stability samples will not have to be analyzed (10). It should be noted that all test substance containers must be retained for the duration of the study i.e., until the study director signs the final report. A conditional exception for disposing of the containers may be obtained by writing to the OCM (11). OCM will set forth certain documentation requirements that will be required to account for the test substance containers. 

Fuller, S. R., and Gamer, W. Y., Test Substance and Analytical Reference Standard Characterization and Accountability In Good Laboratory Practice Standards Applications for Field and Laboratoiy Studies (1992) Willa Y. Gamer, Maureen S. Barge, James P. Ussary, Eds. ACS Professional Reference Book, American Chemical Society, Washington, DC. 

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