Chemical sterilization

Use Herbicide, especially for control of Johnson grass on cotton soil sterilant chemical warfare timber thinning. 

Reactor operation. The polypropylene hollow fibers in the reactor were prewetted prior to inoculation with recirculation of 50% ethanol and sterilized chemically with 5% formalin solution. Then the reactor was washed by ultrafiltration of one liter of autoclaved distilled water. The reactor was placed in a water bath maintained at a desired temperature. Cells were inoculated through the inoculation port using a syringe needle. The detailed experimental setup is shown in Figure 3. 

Besides sterilization, chemical resistance is generally an important attribute that blends and alloys in medical applications must possess. Key chemical agents that must be evaluated include saline solution, isopropyl alcohol, ethyl alcohol, betadyne, chlorine bleach, and lipids. 

Key properties are its flexibility, translucency, and resistance to all known chemicals except molten alkali metals, elemental fluorine and fluorine precursors at elevated temperatures, and concentrated perchloric acid. It withstands temperatures from —270° to 250°C and may be sterilized repeatedly by all known chemical and thermal methods. 

Pesticides are susceptible to a variety of transformations in the environment, including both chemical degradation and microbial metaboHsm. Microbial transformations are catalyzed exclusively by enzymes, whereas chemical transformations are mediated by a variety of organic and inorganic compounds. Many pesticide transformations can occur either chemically or biologically. Consequentiy, most pesticide dissipation studies include sterile treatments to... 

Carboxyhc acid ester, carbamate, organophosphate, and urea hydrolysis are important acid/base-catalyzed reactions. Typically, pesticides that are susceptible to chemical hydrolysis are also susceptible to biological hydrolysis the products of chemical vs biological hydrolysis are generally identical (see eqs. 8, 11, 13, and 14). Consequentiy, the two types of reactions can only be distinguished based on sterile controls or kinetic studies. As a general rule, carboxyhc acid esters, carbamates, and organophosphates are more susceptible to alkaline hydrolysis (24), whereas sulfonylureas are more susceptible to acid hydrolysis (25). 

Industrial sterilization cycles tend to vary considerably, not only from manufacturer to manufacturer, but often from product type to product type, depending on the bioburden present on a given load. Chemical indicators have historically been used only to differentiate between sterilized and nonsterilized packages. More recent developments have resulted in the availability of chemical dosimeters of sufficient accuracy to permit their appHcation either as total monitors or as critical detectors of specific parameters. 

The term steam quaUty refers to the amount of dry steam present relative to Hquid water in the form of droplets. The steam deUvered from the boiler usually contains some water. Excessive amounts can result in air entrapment, drying problems following exposure, and unacceptable steam levels (>3% water or <97% quaUty steam). Excessive amounts of water deposits dissolve boiler chemicals onto the load to be sterilized. Boiler chemicals are used to prevent corrosion in the lines. Inappropriate boiler chemicals, also called boiler amines, may introduce toxicity problems (see CORROSION AND CORROSION control). 

Chemical dosimeters based on ferrous sulfate, ferrous cupric sulfate, or ceric sulfate are generally used. Color-change process indicators are also used, but these cannot measure the radiation dose, only the extent of sterilization. 

Other chemicals used historically as Hquid sterilants include a solution based on hydrogen peroxide (qv). This was once offered commercially. 

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