Reaction methods aspirator

Finding a coordinate system that minimizes the coupling between the DOFs has always been a natural aspiration in theoretical chemistry. The so-called reaction-path formalism is just such a procedure, as is the use of Normal-Form theory [13], which is our method of choice. Normal-Form theory gives us sufficient conditions for a Hamiltonian to be transformed into the form of Eq. (1) in the neighborhood of an equilibrium point of center (g) center g) saddle type. This result is well known (see, e.g.. Ref. 13). To summarize, first we perform a Taylor expansion of the Hamiltonian [Eq. (1)] ... 

The method of specimen delivery within the analyzer is the major difference between continuous-flow and discrete systems. In continuous-flow systems, the specimen is aspirated through the sample probe into a continuous reagent stream, whereas in discrete analyzers, the specimen is aspirated into the sample probe and then delivered through the same orifice into a reaction cup or other container. 

The enzymatic method for determination of cholesterol Is based on that of Klose et al. [15], as modified by Leon and Stasiw [16]. It involves the use of cholesterol stearase to hydrolyse the cholesterol esters In serum to free cholesterol, which Is oxidized to HzCte that In turn forms a qulnonelmlne dye. The reaction is quantitative, so the concentration of the dye formed Is directly proportional to that of cholesterol In the sample. Figure 14.4 Illustrates the function of the SMAC channel used for the determination, in which the reagent stream (cholesterol oxidase, cholesterol stearase, peroxidase, phenol and 4-aminophenazone), the sample and some air are aspirated by the pump and, after mixing in reactor Ri, are Incubated for 4 min in a bath at 37 C, after which the dye Is extracted Into alcohol and sent to the detector, where Its absorbance Is measured at 525 nm. The aqueous phase from the extraction and the cell waste are aspirated by pump P2. The method has fewer and less serious interferences than Its non-enzymatic counterpart. 

Figure 5.13. Determination of chloride by the mercury thiocyanate method with the hydrodynamic injection manifold in Fig. 5.12a, where C was 100 cm long and the volume of conduit L was 25 xL. The pumping rate x = z was 1.1 mL/min and the aspiration rate y was 3.0 mL/min, operated for 12 s. The detector was tuned at 490 nm. (a) Standard calibration run of samples in the range 10-50 ppm Cl (b) stopped-flow experiment with the 40 ppm Cl standard recorded at high paper speed to demonstrate the fast rate of reaction and (c) monitoring of the content of chloride in a solution of NaCl in which the analyte concentration was changed intermittently and measured at fixed time intervals by the system.

My own experience with this reaction dates to the early 80s, when I decided to torment myself by trying it. Detailed cooking procedures using it can be found in Pikhal under MDMA. My experience with the KOH isomerization was that the conversion of safrole to isosaffole went cleanly at about 100% yield, as long as traces of moisture were excluded from the reaction. The conversion of isosafrole to methylenedioxy-phenylacetone is another matter. The yields are low, a lot of work is required because the formic acid and hydrogen peroxide must be removed from the reaction mixture under a vacuum before final treatment with sulfuric acid solution to yield the phenylacetone, and these vapors corrode the aspirator supplying the vacuum. This method stinks ... 

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