Quantitation selectivity

Typical performance characteristics that should be considered in the validation are precision, accuracy, limit of detection, limit of quantitation, selectivity, range, linearity, robustness, ruggedness... 

An ordered antibody array has also been assembled on the solid surface by a combination of Langmuir Blodgett (LB) film method and self-assembling method. An ordered monolayer of protein A is deposited on the solid surface by LB method, which is followed by self-assembling of antibody. Individual antigen molecules which are complexed with the antibody array have been quantitated selectively by atomic force microscopy (AFM). 

A suitable method for this was introduced by Caspersson (mid-1920s-ca. 1940) who designed and successfully exploited UV microscopy so that the extent of the absorbtion could be determined quantitatively. Selective hydrolysis by RNAase or DNAase was used so that the DNA content of the cell could be estimated. The procedure still required reproducible preparation of sections to allow light to be transmitted and the enzymes to get access to the nucleic acids. 

Regulatory requirements in the field of drug residues analysis are limited, in most cases, to the identification of only the major metabolites. Quantitative selection of major over minor metabolites is certainly devoid of rational biological ground, since several studies have shown that the toxic metabolites are usually transitory and often present in small quantities. However, isolation and identification of all these metabolites are difficult and proper assessment of the toxicity of drug residues is still a real challenge. 

The treatment of this diol with DDQ leads to the quantitative selective oxidation of the allylic alcohol, while Mn02 produces an aromatization to the corresponding catechol in... 

Garland, W. A. Powell, M. L. 1981. Quantitative selected ion monitoring (QSIM) of drugs and/or drug metabolites in biological matrices. J. Chro-matogr. Sci., 19,392-434. 

Fig. 27 Examples of thermodynamically controlled reactions employed in the near-quantitative synthesis of MIMs. (a) Disulfide-exchange reaction permits equilibration between a bis(ammo-nium) disulfide dumbbell and a crown ether macrocycle to yield a mixture of [2]- and [3]rotaxanes quantitatively [194], (b) Olefin metathesis at high concentration on a benzylic amide macrocycle greatly favors the catenated species [196]. (c) Self-correcting imine bonds allow for nearly quantitative selection of a [2]rotaxane from an appropriate dynamic combinatorial library [76], (d) A weak nucleophile (E) equilibrates the components of a donor-acceptor [2]catenane in a dynamic Sn2 reaction [205]...

A qualitative assessment of the above factors is often made, but it is also possible to use a value scale to assign points to the various features of a method weighted according to their relative importance the latter approach allows a more quantitative selection process. Decisions can then be made regarding the analytical methods that best fit the laboratory s requirements and that have the potential for achieving the necessary analytical quality. 

In summary, quantitative, selective, and heterogeneous metal assembly was accomplished using a predesigned peptide template. Peptides with the predetermined number and sequence of metal coordination sites would allow template-directed arrays of metal-containing nanosized devices. 

At the molecular level, nature s catalysts, the enzymes (isolated or as microbial systems) provide tremendous rate increases over the corresponding uncatalyzed reactions and virtually quantitative selectivity. The capability to both improve selectivity to a single product and utilize alternate feedstocks is well documented (3-4). 

HI In any given system the number of the components is definite, but may alter with alteration of the conditions of experiment. A certain freedom of choice, however, is allowed in the (qualitative, not quantitative) selection of the components, the choice being influenced by considerations of simplicity, suitability, or generality of application. ... 

ABSTRACT The previous methods of accident cases selection in the past were unsystematic, incomplete and were only limited to qualitative selection. In this article, a large number of accident cases are analyzed, and then the influence factors of high degree of recognition are got as the factors for the selection of coal mine accident cases by filtering the questionnaires. AHP is used to determine the weight of each factor. Finally, a set of quantitative selection method of accident cases is worked out which is used to select cases for training a certain kind of unsafe act. 

Mechanosynthesis was also used by Lamaty et al. to prepare a set of Boc-, Bz-, Fmoc-, and tosyl-hydrazones 68 from aldehydes by employment of Retsch MM200 mill (5mL stainless steel jar, 2x5mm balls). Aromatic, heteroaromatic, and alkyl aldehydes readily reacted under solvent-free conditions with stoichiometric amounts of hydrazines obtaining products quantitatively (selected results are given in Scheme 3.17) [15]. When the reaction was complete, the product was recovered as a solid directly in the jar and dried. The mechanochemical activation was shown to be essential to obtain a... 

The oxidative dehydrogenation of 2-hydroxyaniline is also catalyzed by cobaloxime(II) derivatives with a nearly quantitative selectivity to 26 [46]. 

Method validation is the process of showing that a new procedure or an existing procedure applied to a new type of sample meets specifications and is acceptable for its intended purpose. Standard methods published by government and private agencies are validated by multiple labs before they are published. In pharmaceutical chemistry, method validation requirements include studies of selectivity, accuracy, precision, linearity, range, robustness, limit of detection, and limit of quantitation. Selectivity, accuracy, and precision were mentioned in Section 5-1. 

Separation stages and chemical reactions, e.g., for decomposition or pha.se transformations, are essential components of combined analytical procedures [52], [53]. They should be reproducible. quantitative, selective, and unequivocal. 

With alkanes that have more than one kind of hydrogen, free radical halogenation will usually lead to a mixture of constitutional isomers. Which isomer dominates will depend upon the relative reactivity and number of different hydrogens that can be abstracted. Whi le the structure of the substrate determines which sites are the more reactive, the quantitative selectivity of a reaction will depend upon the reactivity of the halogen radical atom. 

Mant and Hodges [47] developed more quantitative selectivity parameters for peptide separations using RPLC for control de-novo design of synthetic peptide standards with the same (amino acid) composition and minimal sequence variation (SCMSV). They used a range of stationary phases (C8 and C18 alkyl, polar embedded, polar endcapped, ether-linked phenyl, and phenylhexyl) such as those already available for small molecules, further enhancing the universal value of... 

One of the first applications of CI-SIM to drug analysis involved the development of an analytical technique to quantitate selected anti-neoplastic agents (20). To test the method, an equimolar mixture of 5-fluoro-2 -deoxyuridine, 6-mercaptopurine ribonucleoside and arabinosylcytosine were added to mouse serum. Extraction and flash methylation yielded the methylated derivatives (15, 16 and respectively Fig. 7) which could be separated by GC. Th selected ion profiles of this extract, obtained by monitoring the MH of each derivative are shown in Fig. 8. This method has been used for the quantitation of arabinosylcytosine in mice serum (20). 

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