Chromic Acid Cleaning Solution

This left something else as the possible cause of the variability. When we considered the nature of the test, which was sensitive to parts per million of organic materials, we realized that one possibility was contamination of the glassware by the soap used to clean it. We next cleaned all glassware with chromic acid cleaning solution, and reran the tests, with the result as shown in Table 9-5. 

Sealstix. TM for a cement of the deKhotinsky type which adheres to almost any surface insoluble in all common reagents except alcohol, strong caustics, and chromic acid cleaning solution. 

In addition to the blank, which received no special cleaning, treatments with concentrated hydrochloric acid, chromic acid cleaning solution, and l%Alconox solution (an alkaline detergent) were employed. 

The use of chromic acid cleaning solution must be avoided to prevent introduction of chromium. Flasks should be kept covered with inverted beakers to eliminate contamination from dust. 

Dodecanethiol and 11-mercapto-l-undecanol were purchased from Aldrich Chemical Company, Inc. (Milwaukee, WI) and used as received. Glassware for the preparation of SAMs was cleaned with chromic acid cleaning solution (Fisher Scientific). Gold shots (99.99%) were purchased from D.F. Goldsmith. Glass beads (10-30 pm) from Polyscience were used for the normal force calibration. The faceted... 

Slow responding electrodes are easily rejuvenated and cleaned by dipping in warm (60 C) chromic acid cleaning solution for about two minutes. The electrodes are then exercised by dipping alternatively in hydrochloric acid (0.1 N) for about one minute and sodium hydroxide (0.1 N) for about one minute. The exercising is continued until an optimum response time is observed. The electrode is then stored in the hydrochloric acid solution before standardization. 

Unplug and rinse three times in cold water. Let water drain for 5 minutes before placing in chromic acid cleaning solution. ... 

Chromic Acid Cleaning Solution, or a nonchromium-containing, strongly oxidizing acid cleaning solution. 

A method which is frequently used consists in filling the apparatus with chromic acid cleaning mixture (CARE), a nearly saturated solution of powdered sodium dichromate or potassium dichromate in concentrated sulphuric acid, and allowing it to stand for several hours, preferably overnight the acid is then poured off, the apparatus thoroughly rinsed with distilled water, and allowed to drain until dry. [It may be mentioned that potassium dichromate is not very soluble in concentrated sulphuric acid (about 5 g per litre), whereas... 

Chromic acid or nitric + sulfuric acid cleaning solutions are corrosive and need to be handled with care see p. 642. Wear safety goggles and gloves while cleaning the viscosimeter. 

Aluminum can be cleaned in the same fashion as steel. Alternatively, it may be prepared for bonding by chemical etching. For instance, cyanoacrylates cure rapidly to give strong, durable bonds on aluminum etched by Forest Products Laboratory (FPL) chromic acid etching solution. 

The easiest electrode to clean is the spear-type. This is done by dipping it in warm chromic acid cleahing solution for about two minutes. The electrode should then be exercised as described above until stable reproducible readings are obtained. The internal capillary microelectrode can be cleaned by suctioning chromic acid into it and rising it out with water followed by exercise. I have not had any experience cleaning recessed-tip microelectrodes, but assume that chromic acid could be used. 

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