Reagent water

Nitroso-l-napbthol-4-sulfonic acid (3H2O) [3682-32-4] M 316.3, m 142-146°(dec), pK ,t -6.3 (OH). Crystd from dilute HCl soln. Crystals were dried over CaCl2 in a vacuum desiccator. Also purified by dissolution in aqueous alkali and pptn by addition of water. Reagent for cobalt. 

Solution 2 Dissolve 5 g sodium metaarsenite in 100 ml water. Reagent 2 Redox reaction... 

Methanol, ethanol, acetonitrile, benzene, trifluoroacetic anhydride, triethylamine, distilled water reagent grade (Wako Pure Chemical Industries, Ltd, Japan) Methanol, distilled water specially prepared reagent for HPLC (Wako Pure Chemical Industries, Ltd, Japan)... 

Methanol, n-hexane, ethyl acetate, distilled water, sodium chloride, sodium sulfate, reagent grade for residue analysis (Wako Pure Chemical Industries, Ltd, Japan) Acetonitrile, methanol, distilled water, reagent grade for high-performance liquid chromatography... 

To 50 mL of solution passed through cadmium column, add 2 mL of color reagent and mix. Allow the solution to stand for 30 min Measure the absorbance at 543 nm against a distilled water-reagent blank. Read the concentration of N03 -N from the prepared standard curve. Standards should be reduced exactly like samples. 

To measure the folding equilibrium of the Tetrahymena L-21Sca ribozyme in various counterions, 32P-labeled ribozyme is prepared by T7 in vitro transcription with a-[32P]-ATP, according to established protocols (Zaug et al, 1988). Free label is removed with a size-exclusion spin column (e.g., TE-10, BD Sciences), and the RNA used without further purification (Emerick and Woodson, 1993). If desired, the RNA can be end-labeled with 32P and purified by denaturing PAGE. As for all biochemical experiments on RNA, care must be taken to use water, reagents, and plastic consumables that are free of RNase. 

Sulfurous acid (H2S03) is a colorless liquid, prepared by dissolving sulfur dioxide (S02) in water. Reagent grade sulfurous acid contains approximately 6% sulfur dioxide in solution. 

In a closed system with a circulating air pump, connect a calcium chloride drying tube and an aerator inserted in a 300-mL reaction vessel so that air passed through the treated preparation contained in the reaction vessel evaporates any metallic mercury present. In a similar manner, treat 100 mL of the Test Solution and 100 mL of water (reagent blank), and determine the maximum absorbances at the same wavelength. The absorbance of the solution from the Test Solution does not exceed that of the solution from the Standard Solution. 

These points were investigated by a series of experiments involving the water washing of a Peruvian cotton textile that was approximately 800 years old. Various treatments were tested by subjecting suitable size samples to washing with tap water, reagent grade distilled-deionized... 

Types of water Nanopure water River water Reagent water Groundwater Tap water O) S ... 

A pyrochlore of the approximate composition Pb2 [Ru 133Pbo 67] 06 S may be synthesized by first preparing an aqueous solution source of lead and ruthenium cations in a 2 1 lead-to-ruthenium ratio as follows 5.0 g of commercially available Ru(N03)3 solution, 10% (wt.) ruthenium metal (0.005 mole ruthenium metal) is diluted with 25 mL of distilled water. Reagent grade Pb(N03)2 (3.277 g, 0.010 mole) is dissolved in 100 mL of distilled water and added to the ruthenium aqueous solution. This aqueous solution of lead and ruthenium is then stirred for approximately 10 min. 

Amino acids are distributed ubiquitously throughout much of the earth s crust, including the atmosphere (IJ. Their occurrence and important role in living organisms are well known, but amino acids have also been found in fossils and rocks hundreds of millions of years and even billions of years old (2. Amino acids have been reported at parts-per-billion levels in extra-terrestrial samples such as the Apollo moon rocks as well as in several meteorites (3,4). Even distilled water, reagent-grade HCl and other chemicals frequently contain trace amounts of amino acids. Figure 1 summarizes the levels of amino acids found in several samples of environmental Interest. 

Mineral - reagent + water-reagent water-product. 

Uses Reagent for detection of free chlorine in water reagent for analysis of gold curing agent for urethane resins intermediate in prod, of azo dyes... 

All reagents and solutions used in these protocols should be of molecular biology grade and prepared with sterile distilled water. Reagents for some of the protocols are available commercially as kits, and these are indicated. 

For the determination of trace metals in biological materials, in addition to Good Laboratory Practice further particularities have to be respected because the metal concentration in the matrix is extremely low. The most important disturbances are caused by contamination. The falsification of the results can be so enormous that these become nonsensical. Sources of contamination include the utensils used in sample preparation, all equipment having contact with the samples in the analytical procedure, water, reagents, and components in the environment. Because of the low metal content in the samples, instability of the solutions and matrix effects play an important role. Therefore standards and reference materials as well as the analytical procedure have to meet extremely high requirements [35,36]. 

Coumarin, potassium bromide, and potassium ferrioxalate were reagent grade and used without further purification. 3-Cyclodextrin was purchased from Nichiden Chemical Co. Ltd. and purified by recrystallization once from 1-propanol and twice from water. Reagent grade organic solvents were purified and dried by standard methods [19]. Cis- and trans-head-to-head dimers of coumarin were obtained from the irradiation of coumarin in formic acid and in benzene without or with a small amount of benzophenone, respectively, by the similar method of Schenck and Krauch [12,14], An inclusion complex of coumarin with 3-cyclodextrin was obtained as follows equimolar aounts of coumarin and the cyclodext-... 

The bromine-water reagent yields solid bromo derivatives of phenols in several cases. These solid derivatives can be used to characterize an unknown phenol. Procedures for preparing these derivatives are given in Appendix 2. 

Bromine Water. Aromatic amines, since they possess an electron-rich aromatic ring, can undergo electrophilic aromatic substitution with bromine, to yield the corresponding arylamino halide(s). Therefore, if elemental tests indicate that an aromatic group is present in an amine, treatment with the bromine water reagent may indicate that the amine is attached to an aromatic ring. 

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