Trichloroacetic acid 100 percent

Ethanol formulations of salicylic acid (20 and 30%) are used for combination peeling (see salicylic acid section). Trichloroacetic acid is prepared as an aqueous solution, since ethanol solutions do not penetrate the skin. It is prepared by mixing the appropriate concentration of crystals with up to 100 cc of distilled water. Ten and fifteen percent TCA is prepared by mixing 10 or 15 g of crystals in up to 100 cc of total volume, respectively. Aqueous solutions of TCA remain stable for up to 6 months unless contaminated. Other methods have been used to formulate TCA peeling solutions however, the weight/volume methods appear to be the most reliable formulation [5]. Premixed TCA solutions are available from a variety of medical... 

To determine the optimal reaction time for a particular radioiodination, 5 pi aliquots of the reaction medium can be removed every 30 seconds, diluted 1 20,000 with 20 mM Tris, 1 mM ethylenediaminetetraacetic acid (EDTA), pH 7.4, containing 0.5 mg/ml BSA as a carrier protein. Finally, precipitate a small amount of the diluted aliquot with trichloroacetic acid (TCA, 60 percent), centrifuge to recover the pellet, wash the pellet once with TCA, and measure the amount of radioactivity in the pellet and supernatant using a gamma counter. The reaction period representing optimal radiolabel incorporation should be used for subsequent radioiodinations. 

There is a great deal of interest in the determination of lead, particularly micromethods applicable to the analysis blood lead in children. Consequently, reports continue to appear on the atomic absorption determination of lead in blood and urine. Ninety percent of blood lead is found in the erythrocytes and, therefore, whole blood is analyzed rather than serum or plasma. Berman etal. 134) have described a procedure for determining normal lead levels in which only 250 fd of blood are taken. The blood is deproteinized with 1 ml of 10 % trichloroacetic acid and then the lead is extracted with APDC into 1 ml of MIBK, at pH 3.5. 

Plesch, Polanyi, and Skinner [28] found that HC1, S02, C02, EtOH, and EtzO were not cocatalysts, and the last two substances were shown to be inhibitors in that the addition of moist air to a solution containing them did not induce polymerisation. The search for co-catalysts other than water led to the discovery that trichloroacetic acid, sulphuric acid, and 20 percent oleum would act as a co-catalyst to titanium tetrachloride in hexane at about -75°, though none of these acids alone showed any catalytic activity under these conditions [9, 71]. 

Copper-catalyzed monoaddition of hydrogen cyanide to conjugated alkenes proceeded very conveniently with 1,3-butadiene, but not with its methyl-substituted derivatives. The most efficient catalytic system consisted of cupric bromide associated to trichloroacetic acid, in acetonitrile at 79 °C. Under these conditions, 1,3-butadiene was converted mainly to (Z )-l-cyano-2-butene, in 68% yield. A few percents of (Z)-l-cyano-2-butene and 3-cyano-1-butene (3% and 4%, respectively) were also observed. Polymerization of the olefinic products was almost absent. The very high regioselectivity in favor of 1,4-addition of hydrogen cyanide contrasted markedly with the very low regioselectivity of acetic acid addition (vide supra). Methyl substituents on 1,3-butadiene decreased significantly the efficiency of the reaction. With isoprene and piperylene, the mononitrile yields were reduced... 

Deterniine the percent incorporation by TCA precipitation. Remove 2 oL of the reaction mix. Add 8 jL of DEPC-treated H O, and spot 5 pL onto a Whatman GFC filter and reserve it. To the other 5 pL, add 25 pL of 2 mg/mL bovine serum albumin (BSA) and 100 pL of 20% trichloroacetic acid (TCA). Incubate on ice for 30 min, and then filter through GFC in a vacuum filtration device. Wash with 20 mL of 5% TCA, and then dry the filter for 20 min at 60°C or under a heat lamp. Transfer both filters to scintillation vials, add scintillation fluid, and count. Determine the percent incorporation of the trace label into cDNA. The yield in nanograms of cDNA is incorporation xl20 (nmol each nucleotide) x4 (nucleotides) x330 (g/mol of nucleotide). 

A hygroscopic mixture of trichloroacetic acid (FM 163.39) and dichloroacetic acid (FM 128.94) containing an unknown quantity of water weighed 0.721 g. On controlled potential electrolysis, 224 C passed at —0.90 V, and 758 C were required to complete the electrolysis at — 1.65 V. Calculate the weight percent of each acid in the mixture. 

What is the (a) degree of ionization and (b) percent ionization of trichloroacetic acid in a 0.035 M CCI3COOH solution ... 

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