Trichloroacetic acid choice

The use of trichloroacetic acid followed by amine/Freon extraction appears to be the method of choice in the analysis of erythrocyte or tissue nucleotides. In addition to a high recovery for many ribonucleotides, the method is most effective at removing proteinaceous materid. 

The use of metaphosphoric acid solutions for the extraction of ascorbic acid from plant and animal tissues was first proposed in 1935 (29). Metaphosphoric acid, along with trichloroacetic acid, remain as the reagents of choice. Besides the decreased tendency for hydrolysis of the lactone ring, metaphosphoric acid inhibits the catalytic oxidation of ascorbic acid by metal catalysts, such as copper and iron ions, and it inactivates the enzymes that oxidize ascorbic acid. Oxidation of ascorbic acid, which apparently is the result of the action of oxyhemoglobin, may occur when animal tissues are ground with metaphosphoric acid. This... 

If there were a secret to safety, it would lie in a thorough knowledge and understanding of this type of treatment. For doctors to give patients a wide range of choice, they must know how to use at least the three main types of conventional peels correctly alpha-hydroxy acids (AHAs), trichloroacetic acid (TCA) and phenol (for phenol, the doctor should at least know how to apply it locally). For each type of peel, the doctor must be perfectly acquainted with its indications, results, limitations and complications to be able to choose the right product for a given patient and to be able to apply it correctly. The patient should be informed of alternative techniques, their possibilities, contraindications, side-effects and cost. 

For blots with protein amounts less than 50 ng/band, the Ponceau red staining is the method of choice. Aurodye and copper iodide can be used for protein amoimts less than 50 ng/band. Li et al. (1989) compare different protein staining methods. Ponceau red stains protein on nitrocellulose blots (see Table 1.2). The staining is reversible and allows subsequent immu-nostaining. The blot is incubated for 1 to 2 minutes at RT in Ponceau red (2% in 3% trichloroacetic acid), and the surplus stain is then washed away with water. 

Several methods are available for the analysis of tetrachloroethylene in biological media. The method of choice depends on the nature of the sample matrix required precision, accuracy, and detection limit cost of analysis and turnaround time of the method. Since tetrachloroethylene is metabolized in the human body to trichloroacetic acid (TCA), TCA may be quantified in blood and urine as an indirect measure of tetrachloroethylene exposure (Monster et al. 1983). It should be pointed out that the determination of TCA may not provide unambiguous proof of tetrachloroethylene exposure since it is also a metabolite of trichloroethylene. Trichloroethanol has also been thought to be a metabolite of tetrachloroethylene, identified following occupational exposure (Bimer et al. 1996 Ikeda et al. 1972 Monster et al. 1983). However, rather than being a metabolite of tetrachloroethylene, it is more likely that trichloroethanol is formed from trichloroethylene, which is often found as a contaminant of tetrachloroethylene (Skender et al. 1991). Methods for the determination of trichloroethylene and trichloroethanol are summarized in the Toxicological Profile for Trichloroethylene (ATSDR 1993). 

Chemical peeling wim trichloroacetic acid (TCA) is a good choice to treat senile lentigos. The application of this agent on the skin causes protein denaturation... 

The method of choice for serum iron analysis has been recommended by the International Committee for Standardization in Haematology (ICSH) [42]. This reference procedure obviates problems that are inherent in convenient automated methods that are precise but inaccurate [43]. In the recommended reference method, iron is released from transferrin with trichloroacetic acid (TCA), which precipitates apotransferrin and other serum proteins that are removed by centrifugation. Fe in the supernatant fluid is reduced to Fe " with thioglycolic (mercaptoacetic) acid, which is then complexed with a chromogenic iron-chelating reagent whose color is proportional to iron concentration. 

Quantitative Determination of Trichloroacetic Acid as an Indicator of Trichloroethylene Poisoning. Methodological Review and Choice of a Gas Chromatographic Method G. Ital. Med. Lav. 2(1) 27-31 (1980) CA 93 198587h... 

Dissolve 100 mg. of ascorbic acid of the highest purity in 100 ml. of 5% metaphosphoric acid-10% acetic acid solution or 4% trichloroacetic acid solution, the choice being the extractant used in the method. Oxidize this solution with bromine as directed above. Pipet 10 ml. of the dehydroascorbic acid solution obtained into a 500 ml. volumetric flask, and make up to the mark with the acid solution used in the method. 

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