Combination methods

Aj ala P Y and H B Schlegel 1997. A Combined Method for Determining Reaction Paths, Minima and Transition State Geometries. Journal of Chemical Physics 107 375-384. 

By connecting a gas chromatograph to a suitable mass spectrometer and including a data system, the combined method of GC/MS can be used routinely to separate complex mixtures into theii individual components, identify the components, and estimate their amounts. The technique is widely used. 

Among the many, such combination method, which allows to combine the sorption concentration and the subsequent photometrical determination in solid phase, as solid-phase spectrophotometry (SPS), proves to be very effective in the analysis. 

A combination of dimensional similitude and the mathematical modeling technique can be useful when the reactor system and the processes make the mathematical description of the system impossible. This combined method enables some of the critical parameters for scale-up to be specified, and it may be possible to characterize the underlying rate of processes quantitatively. 

You can choose any of a number of methods for conducting these checks. One involves developing a systematic checklist or grid that displays the criteria themselves and checks each modification against them. In addition, as with previous exercises, it s often useful to call on your colleagues on the PSM team, or on other advisors, and ask them to play devil s advocate. It s often useful to combine methods such as these, because together they yield both a quantitative assessment ("Does this modification do what we said we wanted it to do ") and a more qualitative judgment ("Will this modification work in actual practice "). 

For single-carbon-number AOS samples, analyses can be performed satisfactorily using just the GC method. For multicarbon-number AOS samples that have high sultone content (about 50 ppm), the LC method provides adequate resolution and sensitivity. However, for multicarbon-number AOS samples containing normal sultone levels and for AES samples, the combined LC-GC method is necessary to obtain the required separation and detection levels. Additionally, the combined method is advantageous in eliminating interferences in the LC method that are sometimes observed with AOS samples that have been bleached. 

Crystallization from the liquid metal has been assessed theoretically and experimentally as a purification method for both Sr and Ba After five recrystallizations, metals of 99.9999% purity can be produced. The purification of Ba by zone refining is inefficient, many passes being required for the removal of the other alkaline-earth metals. The application of combined methods (i.e., vacuum distillation plus crystal growthor vacuum distillation plus zone refining ) to the purification of both metals has also been described. 

Gibrid (combined) methods. In mastering the difficulties involved in solving difference elliptic equations, some consensus of opinion is to bring together direct and iterative methods in some or other aspects as well as to combine iterative methods of various types (two-step methods). All the tricks and turns will be clarified for the iteration scheme... 

Many methods of determining individual colorants and blended compositions have been selected, critically reviewed, and published. Combined methods such as paper chromatography, TLC, HPLC, spectrophotometry, voltammetry, and more recently, CZE have been developed. Table 6.6.1 presents some of these methods. 

The various attempts, in the different fields, can be viewed as an effort to combine methods and experience of two disciplines which have reached since longtime their maturity quantum mechanics for isolated systems and statistical mechanics. This effort of combination produces important results, and the progress in this area is indisputable. 

Sugai T., Sugitani M. and Onoda N. (2000). Novel subdivisions of the rat accessory olfactory bulb revealed by the combined method with lectin histochemistry, electrophysiological and optical recordings. Neuroscience 95, 23-32. 

Cyclic oligomers of PA6 can be separated by PC [385,386] also PET and linear PET oligomers were separated by this technique [387]. Similarly, PC has been used for the determination of PEGs, but was limited by its insensitivity and low repeatability [388]. PC was also used in the determination of Cd, Pb and Zn salts of fatty acids [389]. ATR-IR has been used to identify the plasticisers DEHP and TEHTM separated by PC [390]. Although this combined method is inferior in sensitivity and resolution to modem hyphenated separation systems it is simple, cheap and suitable for routine analysis of components like polymer additives. However, the applicability of ATR-IR for in situ identification of components separated by PC is severely restricted by background interference. 

Figures 3-4 and 3-5 show the optimized paths with the added images and the original combined method [27] and parallel path optimizer method [25] calculated paths for the first and second steps of the reaction respectively. In both cases, the addition of extra images on the converged path, and subsequent optimization of these extra images produces a smoother path since the additional images allows for a better mapping of the potential energy surfaces (PESs).

DFTB has been combined with various force field programs, including CHARMM [49], Amber [50, 51], SIGMA [52], TINKER [34] and GROMACS (to be published). All these combined methods have used the same strategy for the interface with respect to the treatment of bonding interactions at the interface and non-bonded Coulomb and van der Waals (vdW) terms. The concepts will not be reviewed in detail here, for this purpose we would like to refer to an excellent and extensive recent review [4],... 

A recent study published by Badema et al. in 2011 describes a combined method to investigate the toxicity of an industrial landfill s leachate which is based on a triad approach including chemical analyses, risk assessment, and in vitro assays [17]. Moreover, to verify the applicability and the robustness of the proposed method, the approach was applied on a real case study a controlled, ISO-14001 certified landfill for nonhazardous industrial waste and residual waste from the treatment of MSW in northern Italy for which data on the presence of leachate contaminants are available from the last 11 years. 

Nishiyama and Kuninori [65] described a combination method of assay for penicillamine using HPLC and postcolumn reaction with 6,6 -dithiodi(nicotinic acid). Thiols were separated by HPLC on a reversed-phase column (25 cm x 4.6 mm) packed with Fine Sil 08-10, with 33 mM KH2PO4 (adjusted to pH 2.2 with H3PO4) or 33 mM sodium phosphate (pH 6.8) as the mobile phase. Detection was by postcolumn derivatization with 6,6 -dithiodi(nicotinic acid), and measurement of the absorbance of the released 6-mercaptonicotinic acid was made at 344 nm. The detection limit for penicillamine was 0.1 nmol. A comparison was made with a... 

Table 34-7 Individual sample precision and accuracy for combined Methods A and B and Labs 1 and 2 - Production samples...

Table 35-4 reports ANOVA comparing the METHOD B procedure to the METHOD A procedure for combined laboratories. Thus the combined METHOD B analyses for each sample were compared to the combined METHOD A analyses for the same sample. This statistical test indicates whether there is a significant bias in the reported results for each method, irrespective of operator or location. An apparent trend is indicated using this statistical analysis, that trend being a positive bias for METHOD B as compared to... 

With the combined methods of 29Si NMR spectroscopy, X-ray diffraction, HRTEM and SAED we were able to characterize the Ti-Beta particle growth. 29Si NMR spectroscopy gave us an opportunity to see the formation of nanoparticles even before they were detectable with other techniques such as XRD. The above mentioned techniques enabled us to obtain sufficient knowledge to prepare Ti-Beta nanoparticles which were than successfully incorporated in novel micro/mesoporous materials [1],... 

In a method described by Kiriyama and Kuroda [500], molybdenum is sorbed strongly on Amberlite CG 400 (Cl form) at pH 3 from seawater containing ascorbic acid, and is easily eluted with 6 M nitric acid. Molybdenum in the effluent can be determined spectrophotometrically with potassium thiocyanate and stannous chloride. The combined method allows selective and sensitive determination of traces of molybdenum in seawater. The precision of the method is 2% at a molybdenum level of 10 xg/l. To evaluate the feasibility of this method, Kiriyama and Kuroda [500] spiked a known amount of molybdenum and analysed it by this procedure. The recoveries for 4 to 8 xg molybdenum added to 500 or 1000 ml samples were between 90 and 100%. 

Guillen, C. Martinez, M. A. Herrero, J. 2000. CuInSe2 thin films obtained by a novel electrodeposition and sputtering combined method. Vacuum 58 594-601. 

In order to achieve a uniformly good estimate of the potential of mean force, the difference constants from successive simulation windows has to be perfectly matched so as to make W,(t) agree in the overlapping regions. Optimal data combining methods such as the weighted... 

For each subset chosen in step 4, use a solution combination method to produce one or more combined solutions. 

Alzamora, S.M., Cerruti, S., Guerriero, S., and Lopez-Malo, A. 1995. Minimally processed fruits by combined methods. In Food Preservation by Moisture Control Fundamentals and Applications (G.V. Barbosa-Canovas and J. Welti-Chanes, eds), pp. 463 492. Technomic Publishing, Lancaster, PA. 

Argaiz, A., Welti, J., and Lopez-Malo, A. 1996. Effect of syrup reuse on the quality of fruit preserved by combined methods. In IFT Annual Meeting Book of Abstracts , p. 101. Institute of Food Technologists, Chicago. 

Lopez-Malo, A., Palou, E., Welti-Chanes, J., Corte, P., and Argaiz, A. 1994. Shelf stable high moisture papaya minimally processed by combined methods. Food Res. Int. 27, 545-553. 

Moreno, J., Chiralt, A., Escriche, L, and Serra, J.A. 2000. Effect of blanching/osmotic dehydration combined methods on quality and stability of minimally processed strawberries. Food Res. Int. 33, 609-616. 

Kinetically controlled epoxy curing reactions, 10 423 Kinetic barriers, 11 529 Kinetic friction, 15 224 Kinetic incompatibility, in acrylonitrile copolymerization, 11 203 Kinetic measurements, 14 607-629. See also Very fast kinetics combined methods for unstable reagents, 14 621... 

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