Quantitation linearity

An analytical method vahdation study should include demonstration of the accuracy, precision, specificity, limits of detection and quantitation, linearity, range, and interferences. Additionally, peak resolution, peak tailing, and analyte recovery are important, especially in the case of chromatographic methods (37,38). 

In contrast to the hydrolysis technology, the methanolysis process allows for the one-step synthesis of organosdoxane oligomers and methyl chloride without formation of hydrochloric acid (64,65). The continuous methanolysis can also yield quantitatively linear sdanol-stopped oligomers by recycle of the cycHc fraction into the hydrolysis loop. 

Accuracy and precision Specificity Limit of detection Limit of quantitation Linearity and range... 

Thaler, C. and Vogel, S. S. (2006). Quantitative linear unmixing of CFP and YFP from spectral images acquired with two-photon excitation. Cytometry A 69, 904—11. 

On the basis of these assignments, the two bands must be associated with the presence of isolated Ti atoms in tetrahedral coordination within the silicalite framework. Consequently, a quantitative linear correlation between the Ti02 content and the intensities of both the infrared and Raman bands at 960 cm-1 is expected—and this is indeed observed, as shown in Fig. 9b. 

To validate the suitability of methods, experiments to establish specificity, accuracy, precision, limits of detection, limits of quantitation, linearity, range, and robustness should be conducted. Furthermore, appropriate system suitability criteria should be developed to assure that the method is performing to pre-established criteria at the time of use. 

Wurster in 1879 had already prepared crystalline salts containing radical cation 23 (equation 12). Subsequently, radical cations of many different structural types have been found, especially by E. Weitz and S. Hunig, and recently these include a cyclophane structure 24 containing two radical cations (Figure 3). Leonor Michaelis made extensive studies of oxidations in biological systems, " and reported in 1931 the formation of the radical cation species 25, which he designated as a semiquinone. Michaelis also studied the oxidation of quinones, and demonstrated the formation of semiquinone radical anions such as 26 (equation 13). Dimroth established quantitative linear free energy correlations of the effects of oxidants on the rates of formation of these species. ... 

Limits of detection and quantitation Linearity and range Ruggedness Robustness... 

A global electrophilicity index of common benzylating and acylating agents has been established from MO calculations and it shows a quantitative linear correlation with the experimental substrate selectivity index from a series of benzylation and acylation reactions.21 The values of relative rate coefficients predicted from the index may be accurate to within 10%. The reaction of /-butyl chloride with anisole catalysed by /Moluenesulfonic acid in supercritical difluoromethane has been subject to kinetic analysis.22 The proportions of substitution at the ortho -position and disubstitution increase at lower pressures, attributed to the decrease in the hydrogen-bonding ability of the solvent. 

As per the FDA guidance, the simplest regression model that adequately describes the concentration-response relationship should be used for quantitation. Linear... 

Typical analytical parameters used in assay validation are accuracy, precision, specificity, limit of detection, limit of quantitation, linearity, range, and ruggedness. 

Attimarad [44] developed a reversed-phase HPLC method for the determination of lornoxicam in bulk and pharmaceutical preparation. Separation was performed on an Eclipse Cig column (15 cm x 4.6 mm, pm) as stationary phase and mobile phase used is methanol 0.1% formic acid in water (80 20), with a flow rate of 0.8 ml/min and UV detection at 381 nm. The method was validated for linearity, accuracy, precision, limit of detection, and limit of quantitation. Linearity, accuracy, and precision were found to be acceptable over the range 0.5-20 pg/ml. The method can be adopted for routine quality control analysis of lornoxicam. 

QSAR. Quantitative structure-activity relationships—the science of deriving quantitative linear or nonlinear mathematical relationships between physicochemical and topo-logical/topographical properties of chemical structures and their biological activity. Originally, regression analysis was the only tool used to derive QSAR equations. More re-... 

When oligonucleotides are designed and analyzed using the conditions described above, it is possible to achieve extremely sensitive detection of labeled oligonucleotides using metal nanoparticles [36, 43]. It is possible to achieve quantitative, linear SERRS responses when the concentration of the labeled oligonucleotide is kept below monolayer coverage of the nanoparticle surface. 

Other types of constraints, not corresponding to quantitative linear relations, can also be included, if they fulfill two requirements. The first requirement is that the constraint must possess the following convexity-like property If the constraint is satisfied for two individual pathways, and nil, then it should be satisfied for any positive linear combination of these, = IJii nii + lii,nij, (where > 0, > 0). The second requirement is... 

The United States Pharmacopoeia (U.S.P.) [5] in a chapter on validation of compendial methods, defines analytical performance parameters (accuracy, precision, specificity, limit of detection, limit of quantitation, linearity and range, ruggedness, and robustness) that are to be used for validating analytical methods. A proposed United States Pharmacopeia (U.S.P.) general chapter on near-infrared spectrophotometry [6] addresses the suitability of instrumentation for use in a particular method through a discussion of operational qualifications and performance verifications. 

This is the most common approach in QSAR to develop a quantitative linear correlation model, althongh not necessary always best for a given data set. The simplest means to obtain such a quantitative relationship is to nse MLR available in any statistical software package. MLR generates predictive equations of the form ... 

In addition to many early examples, biological response has been found to be quantitatively linearly dependent on log P or it in the inhibition of the Hill reaction >activity of penicillins, toxicity of benzoic acids to mosquito larvae , phenol coefficients , cholinesterase inhibitors , and catechol-amine activity . 

The analytical procedures to assess stability must encompass the elements common to validating analytical assays. The methods must be validated according to the parameters of accuracy, precision, robustness and specificity, limits of detection and quantitation, linearity of active ingredient assays, degradants, and other reaction products. More information on how to develop stability indicating methods is discussed in Chapter 7. Validation of these methods is discussed in Chapter 8. 

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