Doubly distilled water

A mixture of l,4-dibromo-2,5-bis(3-sulfonatopropoxy)benzene 61 (0.78 g, 1.39 mmol), 60 (0.23 g, 1.39 mmol), Na2C03 (0.99 g) in doubly distilled water (47 mL), and DMF (20 mL) was heated at 85°C until the solids were completely dissolved. The resulting solution was cannulated to a 200-mL Schlenk flask with tris[(sulfonatophenyl)phosphine]palladium(0) (0.045 g) and the mixture was stined at 85°C for 10 h. The reaction mixture was concentrated to 25 mL by boiling and filtered. The filtrate was added dropwise to cold acetone (250 mL) to precipitate out the polymer. The polymer was collected by filtration, redissolved in a minimum of hot water, and reprecipitated by cooling. After repeating this procedure twice, the polymer was redissolved in distilled water and dialyzed for 72 h in 3500 gmol 1 cutoff membrane. After drying under vacuum, polymer 63 was obtained in 64% (0.42 g). 

The flow behavior in miniaturized hemodialyzer modules with two types of biocompatible membrane materials, SMC and SPAN, was investigated by using doubly distilled water as the flowing fluid in both compartments, subsequently termed membrane side (M) and dialysate side (D), respectively (Figure 4.6.1 (c, d)) [12], SMC stands for Synthetically Modified Cellulose and SPAN for Special PolyAcryloNitrile-based copolymer (Akzo Nobel, Membrana GmbH), both types representing standard membrane material. The capillaries made from this hollow... 

The pyrogenic flame hydrolyzed silica Aerosil 200, a commercial product from Degussa, was used as a dispersion in doubly distilled water (1). The precipitated silica was prepared by hydrolysis of orthosilicic acid tetraethylester in ammoniacal solution according to the method of Stober, Fink and Bohn (11). The prepared suspension was purified by repeated centrifugation, separation from solvent and redispersion of the sediment in fresh water. Finally, the water was evaporated and the wet silica dried at 150°C for about half an hour. 

Eberlein and Kattner [194] described an automated method for the determination of orthophosphate and total dissolved phosphorus in the marine environment. Separate aliquots of filtered seawater samples were used for the determination orthophosphate and total dissolved phosphorus in the concentration range 0.01-5 xg/l phosphorus. The digestion mixture for total dissolved phosphorus consisted of sodium hydroxide (1.5 g), potassium peroxidisulfate (5 g) and boric acid (3 g) dissolved in doubly distilled water (100 ml). Seawater samples (50 ml) were mixed with the digestion reagent, heated under pressure at 115-120 °C for 2 h, cooled, and stored before determination in the autoanalyser system. For total phosphorus, extra ascorbic acid was added to the aerosol water of the autoanalyser manifold before the reagents used for the molybdenum blue reaction were added. For measurement of orthophosphate, a phosphate working reagent composed of sulfuric acid, ammonium molyb-... 

Internal purge gas was again diverted through the reaction cell, which was emptied and rinsed with doubly distilled water. The sodium borohydride solution was withdrawn from the injector tip by reversing the direction of the peristaltic pump. The next sample aliquot was then added to the cell and the measurement process repeated. Replicate measurements could be made every 3-4min. 

Taimic acid (TA) was obtained from Merck [K30231073-212]. Stock TA solution (100 pg ttiL ), was prepared freshly with doubly distilled water. 

ABTS (5.8 mg, 0.01 mmol) doubly distilled water centrifuge flasks centrifuge... 

At 20 °C 180, 118, 107, and 126 nmol/L in doubly distilled water. Pacific seawater, artificial seawater and 35% NaCl, respectively (modified shake flask method-fluorometry, Hashimoto et al., 1984)... 

Closely related to issues of substrate purity are concerns related to the purity of the other components of the reaction mixture, especially water. For example, many enzymes that act on amine-containing molecules are inhibited by ammonium ions. As ammonia can be a common contaminant in many laboratories, doubly-distilled water can still contain enough ammonia to perturb certain enzyme activities. In such cases, it is important to test for ammonia and/or to determine the dissociation constant for ammonia with the enzyme under study. 

After cleaning with a phosphate-free detergent, labware should be rinsed extensively with deionized water and finally rinsed at least twice with doubly distilled water before drying. Avoid using paper towels, because lint and microscopic paper fibers often contain metal ions as well as acids/bases used in commercial treatment of paper products. Paper fibers also scatter light and interfere with spectrophotometric assays. 

To determine the allelopathic potential of campestris and oleracea var. italica, leachates from each species were made. Extracts were prepared by soaking, for two hr, weighed amounts of fresh or dried material in sufficient doubly distilled water to prepare a 10% extract (of fresh material) or 1.5% extract (of dry material). Extracts were vacuum filtered through paper (Whatman 1). The osmotic concentration was measured with a freezing-point osmometer (0 to 500 mosm) and indicator seeds were soaked in 10 mL of the extract for an hour prior to planting. 

Extracts (12 mL each) were added to Petri dishes 10 cm in diameter containing 50 g of 30-mesh washed sand covered with filter paper circle (7-cm diameter, Whatman 1). Controls were moistened with doubly distilled water. Ten indicator seeds were placed on the filter paper in each dish with the embryo down and the hypocotyl pointed to the center of the Petri dish. Each indicator/extract combination had 3 replicates. The Petri dishes were kept in a dark growth chamber for approximately 72 hr at 25°C. The radicle length of each germinated seedling was measured at 72 hr. 

When all the fractions were ready, 0.09 g were dissolved in 21 mL of the solvent with which they were extracted and 3 mL used to moisten a filter paper circle (7-cm diameter, Whatman 1). Controls were moistened with 3 mL of the solvent alone. The solvents were allowed to evaporate and the filter papers then placed in the center of Petri dishes containing 50 g of 30-mesh washed sand. The, 12 mL of doubly distilled water were added to each dish in which 10 seeds were set. 

Conductometric titration of the surface groups gave a surface charge density of strong acid (-S0 ) of 0.56 C/g and of weak acid (-COO ) of 0.23 C/g. Preceding the conductometric titration the latex was cleaned by serum replacement with doubly distilled water and 5 10 M HCl as described in ref. ( 3). 

The dielectric constants , which are also needed to evaluate the Debye-Hiickel constants A and B, were measured from 283.15° to 318.15°K at intervals of 5°K, using spectrograde acetone and freshly prepared, doubly distilled water as reference materials. The Janz-Mclntyre bridge (18) with Balsbaugh con-... 

PREPARATION OF CATION-EXCHANGE RESIN. Amberlite CG-120-H cation-exchange resin is placed in a 600 cm3 beaker about 3 g of dry resin (10-meq capacity) is required for each 0.9 x 15 cm column. The resin is covered with 3N NH4OH, swirled for 30-60 min, and allowed to settle. The NH OH is decanted off, and the process is repeated twice. The resin is then washed with doubly distilled water until it is approximately neutral. 

The resin was regenerated with 3N HC1 (three times) as described above and then washed with doubly distilled water until neutral. 

The 0.9 x 15 cm. columns with sintered glass filters (Fischer and Porter, Warminster, PA) are filled about halfway with the wet resin, being careful to avoid channeling. Doubly distilled water is added with more resin. The column is filled to 7 cm, washed with distilled water, and the liquid is drained to the level of the resin before the sample extract is applied. 

Hafnium tetrachloride, nitric acid, and potassium hydroxide solutions were prepared using doubly-distilled water from an all borosilicate glass still. The chemicals were of the highest purity grade commercially available and were used without further purification. 

The resulting pastes, for all cases, were placed into a PVC cylindrical sleeve body. The conducting composite material glued to the copper contact was cured at 40°C during a week. Before each use, the surface of the electrode was wet with doubly distilled water and then thoroughly smoothed, first with abrasive paper and then with alumina paper (see more details on the preparation of GECE in Procedure 7). 

For the calibration of the constructed sensors and the electronic tongue, different stock solutions containing a single ion or both are prepared. These are KC1 solutions in doubly distilled water with concentrations 0.001 M, 0.01 M, 0.1 M and 1.0 M, NH4C1 solutions in doubly distilled water with concentrations 0.001 M, 0.01 M, 0.1M and 1.0 M, plus two KC1 and NH4C1 mixed solutions in doubly distilled water with concentrations of 0.01 M and 0.1 M of both ions, respectively. Accessory materials to facilitate construction and electrical connection are TV antenna coaxial cable, alligator clips (for an easy connection of the coated wire sensors) and epoxy resin (Araldit). 

The model latexes were diluted with doubly distilled water to a concentration of 5 x 104% by weight. Each sample was adjusted... 

The solubility of silver sulfadiazine has been determined by equilibrating the compound in doubly distilled water at 25 C and the measurements of the saturated solution for sulfadiazine by UV spectrometry and for silver by atomic absorption spectroscopy (7). Nesbitt and Sandmann (22) measured the equilibrated solution for silver using a silver-ion selective electrode. Their measurements were performed at 25°C in nitric acid -potassium nitrate buffers (pH 2-3) and ionic strength 0.1. 

Element Subboiling Quartz Still, Doubly Distilled-Water Feed Doubly Distilled in Quartz, Distilled Water Feed" Deionized, Monobed, Polyethylene Apparatus, Distilled-Water Feed" Distilled Two-Stage Commercial Metal Still, City Water Feed," Recirculating Ultrapure System, Metal" Single-Pass Deionization of Tap Water" Deionization, Carbon Absorption, Deionization, Membrane Filtration ... 

---