Staining methods action

The TLC plate is then placed in a glass container with a solvent filled to approximately 1 cm from the bottom. The solvent will move to the top of the TLC plate as a result of capillary action. Since each compound in the mixture will have a unique way of interacting with the matrix and the solvent, some compounds will move faster towards the top of the TLC plate than others. The it /-value is the ratio of the distance of the compound has migrated divided by the distance the solvent has migrated, and has by definition a maximum value of 1. The -value tends to be constant for a given combination of compound, solvent, and matrix so that comparisons can be made between separations performed at different times. If a given compound is colored, it is easy to determine the / -value. For non-colored compounds staining methods are available (see section 1.3). 

Figure 1. Action pattern of Bacillus circulans F-2 amylase. Culture supernatant was applied to PAGE and stained for amylase activity with starch—iodine method. Action patterns of groups I and II toward soluble starch were studied thin-layer chromatography. (Reproduced with permission from ref. 7. Cbpyright 1989 Elsevier.)...

Pickles MJ, Joiner A A new in vitro method for determining toothpaste abrasivity. J Dent Res 2004 83(Spec Iss A) 4032. http //iadr.confex.com/iadr/2004Hawaii/techprogram/abstract 46452.htm Dawson PL, Walsh JE, Morrison T, Grigor J Dental stain prevention by abrasive toothpastes A new in vitro test and its correlation with clinical observations. J Cosmet Sci 1998 49 275-283. Phaneuf EA, Harrington JH, Dale PP, Shklar G Automatic toothbrush a new reciprocating action. J Amer Dent Assoc 1943 65 12-25. 

Some sulfur compounds can also have a corroding action on the various metals of the engine system, varying according to the chemical type of sulfur compound present. Fuel corrosivity is assessed by its action on copper and is controlled by the copper strip test (ASTM D-130, IP 154), which specifies that not more than a slight stain shall be observed when the polished strip is immersed in fuel heated for 2 h in a bomb at lOO C (212°F). This particular method is not always capable of reflecting fuel corrosivity toward other fuel system metals. For example, service experience with corrosion of silver components in certain engine fuel systems led to the development of a silver corrosion test (IP 227). The mercaptan sulfur content (ASTM D-1219, ASTM D-3227, IP 104, IP 342) of jet fuels is limited because of objectionable odor, adverse effect on certain fuel system elastomers, and... 

HCN can be tested calorimetrically. A method suitable for detecting 10 ppm HCN involves the use of test paper treated with j)tira-nitrobenzaldehyde and K2CO3. A reddish purple stain is produced owing to HCN. Its presence in plants, tissue, and toxicologic substances can be tested colori-metrically using 4-(2-pyridylazo)resorcinol-palladium in a carbonate-bicarbonate buffer solution. The intense red color changes to yellow upon the action of HCN (Carducci et al. 1972). 

Using various incubation media, he followed calcium deposition in the matrix by staining the preparation with the von Kossa method. At the pH of the blood plasma, the phosphate and carbonate are present mainly in the form of HPO4, H2PO4, and HCO3 with low levels of PO4 and CO3. To induce calcification, the local condition must in some way raise the level of PO4 and CO3. Robinson thought that this was accomplished by the action of alkaline phosphatase (pH optimum 9), which is found in large quantities in the osteoblasts but is absent in the matrix and the osteoclast. But alkaline phosphatase is rather unspecific except for the fact that it attacks only monophosphates. 

Peterlin et al. [157] described the use of iodine vapor, at 60°C (24 h) to reveal the structure in PE fibrils drawn from solution grown single crystals. Andrews et al. [78] extended this method to prestaining a block of material prior to ultrathin sectioning. They showed the contrast enhancement of PE spherulites by action of the iodine. However, the iodine dissipates upon standing in air and is known to vaporize in the vacuum of the electron microscope. The chlorosulfonic acid method (Section 4.4.4) has replaced iodine staining of polyethylene. 

Empirical Methods, Mayer s mucihematein and mucicarmine methods 94) are classical and widely used stains for mucus. Both mixtures contain aluminum salts whose binding by acidic groups may contribute to the staining action. These methods are not as selective or dependable as others of this group and are not recommended for histological studies. It is of interest that the mucicarmine stain has been recommended for detecting both acid and neutral polysaccharides on filter paper 84b),... 

In another method of testing for nickel in alloys, the surface is freed of grease with ether, and a drop of a solution of 0.5 g dimethylglyoxime in 5 ml 98 % alcohol and 6 ml ammonia is added. A pink fleck of nickel dimethylglyoxime forms and may be made clearly visible by rubbing a piece of filter paper on the stain. The test is more sensitive if the portion of the surface to be tested is oxidized by the action of a blowpipe flame before treating it with the reagent. ... 

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