Soaking glassware

Caution Octamethylpyrophosphoramide is very toxic (see Properties) and must be handled with great care. All work should be conducted in a vented hood rubber gloves and plastic aprons should be worn by all personnel. Typical symptoms of intoxication from this compound are abdominal cramps and diarrhea. A common symptom of acute intoxication is constriction of the pupils of the eyes. In case of accident leading to possible intoxication, get immediate medical attention. Atropine sulfate is a specific antidote. The checkers make it a practice to soak glassware that has been used for octamethylphosphoramide in a 20 per cent sodium hydroxide solution for 24 hours to destroy residues. 

In view of the foregoing remarks, it is clear that all glassware used in the preliminary treatment of samples to be subjected to stripping voltammetry, as well as the apparatus to be used in the actual determination, must be scrupulously cleaned. It is usually recommended that glassware be soaked for some hours in pure nitric acid (6 M), or in a 10 per cent solution of pure 70 per cent perchloric acid, followed by washing with de-ionised water. 

This flask must be cleaned with h ot chromic acid solution and then, along with all other glassware used in this preparation, soaked in a base solution, rinsed with distilled waiter, and oven dried. Thermal rearrangement of the intermediate vinyl ether in a new (untreated) flask resulted in elimination. 

Glassware is cleaned by soaking it overnight in a coned nitric acid bath. 

References to sample contaimination in the literature are numerous. Abercrombie, ef. oJ.(54) have noted that the information obtainable from ICP emission analysis warrants additional care because of the increased number of elements monitored. For example, if one were looking for boron and sodium, the use of glassware should be avoided. Certain digestion vessels that are presumed to be cleaned may not be acceptable. Polyethylene bottles (acid-soaked), for example, have been shown to continue releasing zinc from the matrix for as long as seven days(92). A number of trace elements may be leached from commercial disposable test tubes. Some of the more important contaminants include Ba, Sr, Zr, Na, K, Al, Ca and Mg. 

All toxic materials were disposed of in accordance with "Prudent Practices in the Laboratory" National Academy Press Washington, DC, 1995. Wastes containing chromium, aqueous solutions as well as solids, were collected and disposed of separately. Prior to washing, all glassware laden with chromium by-products, were soaked overnight in a solution composed of 15-20 g of copper beads dissolved in -2 L of 50% aqueous nitric acid. This solution may be kept loosely capped in a fume hood and reused several times prior to disposal. 

Caution The procedure should be carried out in a well-ventilated hood because of the extreme stench of the mercaptan products. All glassware used in the procedure should be soaked in a bleach solution prior to removal from the hood. 

Contaminated glassware should be kept separated from uncontaminated. Contaminated beakers and flasks are placed in the special sink or other container for washing. Clean and wash all equipment with soap and water immediately after the experiment has been completed. If water-insoluble materials are being used, the first washing should be done with an organic solvent such as acetone. Soak contaminated pipets in a container filled with water. All broken glassware is disposed of in the Solid Radioactive Waste container. 

Nitric acid was being used to clean laboratory glassware to a very high state of surface cleanliness by soaking in a bucket of cone, acid for a week. During this time, one of the empty winchesters was inadvertently used as a solvent residues bottle and some 250 ml of diethyl ether was put in. The acid was to be recovered for re-use and it was put back into the original bottles. When the bottle containing ether was refilled and screw capped, after a few seconds it exploded violently [5]. 

Glassware is removed from the soaking baths and cotton wool plugs removed from pipettes (take care not to splash the caustic chloros). 

The fume cupboard is cleaned directly after sample preparation. Any samples, organic solvent waste, chlorinated solvent waste, and aqueous wastes that do not require decontamination are collected into separate, clearly marked waste containers. In the same way, paper and consumable wastes that do not require decontamination are collected in a clearly marked waste box. Materials requiring decontamination must be treated with a proper decontamination solution and disposed of in designated waste containers. Glassware and accessories are flushed with decontamination solution and soaked in potassium hydroxide solution and, if not destroyed, they are washed with alkaline nonphosphorus detergent before further cleaning. 

Hard water deposits could happen if assembled glassware is placed in a sink of water and left to soak for an extended period of time. 

Therefore, glassware should not soak in a base bath for an extended period of time, and the base bath should never be used for volumetric ware. 

Use. All acids must be used in a fume hood. Let the acid soak in the glassware for a short (or long) period of time (as necessary). Swirling with a magno-stirrer and/or heating the acid or oxidizer by use of a steam bath (do not use a direct flame) can facilitate the action. Mineral deposits can often be removed by hydrochloric acid. Metal films can often be removed by nitric acid. 

Use. It is important to wear gloves and safety glasses and to work in a fume hood If you do not have all of these items for safe use of HF, do not use HF as a cleaning material Pour the diluted HF from its plastic storage container into a plastic soaking tank (like a polypropylene beaker). Let the glassware soak in the HF for anywhere from 30 seconds to two minutes. Rinse for at least one minute (or five full flushes) with water. Then rinse with distilled or deionized water. The HF can be reused many times until a decrease in effectiveness is obvious. 

Bacteriological Material. Soak the glassware in a weak Lysol solution, or autoclave in steam. A number of sources recommend soaking the glassware in a 2% to 4% cresol solution. However, the EPA has recently identified cresol as a hazardous material. Because other options are readily available (see Sec. 4.1.1 through Sec. 4.1.9), there is no reason to use the material. If you have any cresol, contact a hazardous materials disposal firm in your area for removal. 

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