Water demineralised

Vinyl chloride Gelatine Trichlorethylene Caproyl peroxide Demineralised water... 

Hoi water rinse 10. Second rinse (demineralised water)... 

In recent years there has been a great increase in the use of demineralised water for rinsing, especially before electrophoretic painting. The demineralised water is generally applied by misting jets at the end of all other pretreatment stages and allowed to flow back into the last rinse tank. 

Increasingly pure demineralised water is recommended for those boilers operating above 60 bar. 

Reagents. In view of the sensitivity of the method, the reagents employed for preparing the ground solutions must be very pure, and the water used should be re-distilled in an all-glass, or better, an all-silica apparatus the traces of organic material sometimes encountered in demineralised water (Section 3.17) make such water unsuitable for this technique unless it is distilled. The common supporting electrolytes include potassium chloride, sodium acetate-acetic acid buffer solutions, ammonia-ammonium chloride buffer solutions, hydrochloric acid and potassium nitrate. 

Cooling water (cooling towers) Chilled water Demineralised water Steam (from direct fired boilers) Compressed air (9 bar) Instrument air (9 bar) (dry) Refrigeration Nitrogen... 

Demineralised water, from which all the minerals have been removed by ion-exchange, is used where pure water is needed for process use, and as boiler feed-water. Mixed and multiple-bed ion-exchange units are used one resin converting the cations to hydrogen and the other removing the acid radicals. Water with less than 1 part per million of dissolved solids can be produced. 

Stein et al. [673] have described a simplified, sensitive, and rapid method for determining low concentrations of cadmium, lead, and chromium in estuarine waters. To minimise matrix interferences, nitric acid and ammonium nitrate are added for cadmium and lead only nitric acid is added for chromium. Then 10,20, or 50 pi of the sample or standard (the amount depending on the sensitivity required) is injected into a heated graphite atomiser, and specific atomic absorbance is measured. Analyte concentrations are calculated from calibration curves for standard solutions in demineralised water for chromium, or an artificial seawater medium for lead and cadmium. 

Dissolve 13.61 gKH2P04in about 900 mlH20 and add 45 ml acetonitrile ( = 45%). Adjust the pH to 2.1 with about 6 ml of 85% orthophosphoric acid and make up to 1 1 with demineralised water. Vacuum filter the solution (0.45 pM filter, Schleicher and Schuell, reference 10410212). 

Reducing reagent dissolve 77 mg dithiothreitol (Roche 708984) in 1 ml demineralised water. 

Deproteinising solution mix 800 ml acetonitrile (Merck 10030) with 200 ml demineralised water and add 1 ml of 98-100% formic acid (Merck 122). 

Internal standard D8-DL-homocystine weigh out 5.56 mg D8-DL-homocystine (ARC/CLI DLM 3619) and dissolve in 20 ml demineralised water, adding one drop of formic acid (1.007 mmol/1). A 2-ml aliquot of this solution is made up to 20 ml with water (100 pmol/1). This is then diluted 1 in 4 (25 pmol/1) with demineralised water (stable for at least 1 year at 4°C). 

Calibration standard, 25 pmol/1 homocystine accurately weigh out 33.6 mg L-ho-mocystine (Sigma H-6010) and dissolve in 50 ml demineralised water. This stock is diluted 1 in 100 with phosphate-buffered saline and stored at -20°C in 150-pl aliquots it is stable for at least 1 year. 

Accurately weigh 1.18 mg of S-adenosylmethionine hydrogen sulphonate (Boeh-ringer Mannheim, cat. no. 102 407, MW 496.2 g/mol) or 1.32 mg of S-adenosylhomocysteine (Sigma cat. no. A 9384, MW 384.4 g/mol). These are dissolved in demineralised water (usually approximately 5 ml) to give a concentration for AdoMet of 0.342 mmol/1 (after correction for the purity declared for the particular batch) and for AdoHcy of 0.686 mmol/1. These solutions are immediately diluted ten-fold with 0.4 mol/1 perchloric acid and can be stored in aliquots at -20 C for at least 6 months. 

HPLC mobile phase A Make 1 ml n-heptafluorobutyric acid (Pierce, 25003) up to 1000 ml with demineralised water. 

Assay buffer (0.4 M K-phosphate buffer pH 6.0) Dissolve 13.93 g K2HP04 (Cat. No. 5101, Merck, Dietikon, Switzerland) in 200 ml demineralised water. Dissolve... 

Dithiothreitol (DTT) (Cat. No. 20710, Serva, Heidelberg, Germany) molecular weight 154.3 Prepare 10 mM solution fresh before use dissolve 1.54 mg DTT in 10 ml demineralised water. 

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