Reagents, ultrapure

Methanol, HPLC grade Sodium chloride, reagent grade Petroleum ether, b.p. 40-60 °C Ultrapure water... 

All reagents and solvents that are used to prepare the sample for analysis should be ultrapure to prevent contamination of the sample with impurities. Plastic ware should be avoided since these materials may contain ultratrace elements that can be leached into the analyte solutions. Chemically cleaned glassware is recommended for all sample preparation procedures. Liquid samples can be analyzed directly or after dilution when the concentrations are too high. Remember, all analytical errors are multiplied by dilution factors therefore, using atomic spectroscopy to determine high concentrations of elements may be less accurate than classical gravimetric methods. 

PCR reaction reagents (Perkin-Ehner and Life Technologies, Inc., Foster City, CA) Ultrapure 100 mM 4(dNTP) stock solution UV-irradiated dH20 Digoxigenin 11-dUTP (Boehringer Mannheim) PCR cocktail, lOX PCR buffer, MgCl2, a set of sense and antisense primers, BSA, Taq polymerase-Taq-start antibody complex (see Note 6). 

The Grignard reagents are prepared by standard procedures.18 If ultrapure metal alkyl products are required, magnesium pieces (Puratronic , Johnson Matthey) should be used otherwise standard magnesium turnings (99.9%, Johnson Matthey 99.95%, Aldrich) will suffice. Methyliodide (99.5%, Aldrich) and ethylbromide (99 + %, Aldrich) are freshly distilled from P205 prior to use. 

The calf thymus dsDNA and ssDNA (as lyophilized powder) were obtained from Sigma-Aldrich Company (Germany). dsDNA/ssDNA stock solutions (lOOmg/L) were prepared with TE solution (10 mM Tris-HCl, 1 mM EDTA, pH 8.00) and kept frozen. More dilute solutions of DNA were prepared with 0.05 M acetate buffer solution containing 20 mM NaCl (ABS pH 4.80) ultrapure distilled water. Other chemicals were of analytical reagent grade. 

Closed systems minimise consumption of reagents and avoid losses of volatile elements. Decomposition vessels should have low trace metal contents and be of extremely pure quartz and PTFE and should be carefully purified prior to use in ultrapure acids or acid vapour (Tschopel et al., 1980) and elemental blanks should be determined for each decomposition vessel. Matusiewicz (1991) has described the special advantages and problems associated with acid vapour-phase digestion procedures. 

So far we have discovered very few polymerization techniques for making macromolecules with narrow molar mass distributions and for preparing di-and triblock copolymers. These types of polymers are usually made by anionic or cationic techniques, which require special equipment, ultrapure reagents, and low temperatures. In contrast, most of the commodity polymers in the world such as LDPE, poly(methyl methacrylate), polystyrene, poly(vinyl chloride), vinyl latexes, and so on are prepared by free radical chain polymerization. Free radical polymerizations are relatively safe and easy to perform, even on very large scales, tolerate a wide variety of solvents, including water, and are suitable for a large number of monomers. However, most free radical polymerizations are unsuitable for preparing block copolymers or polymers with narrow molar mass distributions. 

The manufacture of silicon integrated circuits involves a sequence of inter-related steps, each designed to purify, modify, deposit, or pattern materials. Figure 3 illustrates the principal steps from silicon purification to packaging. A good review of the entire process can be found in Wolf and Tauber [6]. The requirement for ultrapure starting reagents (contaminants... 

Domingo et al. [107, 108] used ultrapure nitric acid for sample digestion, performed all specimen manipulation in a laminar flow hood, carried out readings of a blank (reagents only) for each group of samples and, to minimize matrix effects, prepared the standard curves for aluminum determination by the standard addition method. 

All reagents should be of AR or ultrapure grade. All solutions should be made wth double-distilled water and autoclaved or filter-sterilized where appropriate. Sterile pipetman tips and Eppendorfs, and so on, should be used. 

Reagents and water employed to clean all items and to perform the analysis must be extremely pure. Only reagents with a very low heavy metal content can be used (90). Ultrapure water is produced in a quartz sub-distillation apparatus or with special ion-exchange devices (15, 91, 92). The blanks of pure water and reagents must be checked periodically in order to estimate the metal content added to the samples during analysis. 

Prepare all solutions using ultrapure water and analytical grade reagents. Prepare and store all reagents at room temperature (unless indicated otherwise). 

Luminometer 3550i and Filtravette (New Horizons Diagnostics Corp., USA) were used for bioluminescent measurement. ATP-reagent (based on soluble Luciola mingrelica firefly luciferase) was developed in our laboratory. Dimethyl sulfoxide (DMSO) was from Reakhim (Russia). Nutrition broth (NB) from ICN, Tryptic Soy Broth (TSB) from Difco and Thioglycolate broth (TB) from Merck were used. Ultrapure deionized water was obtained on Milli-Q (Millipore). Broth culture of Escherichia coli LE392 was used in model experiments. 

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