CENTRIFUGE AND FILTERS

The ability to steam-sterilize laboratory media, glassware, and various other supplies is essential to success in the laboratory. Unfortunately, the cost of this piece of equipment parallels that of the microscope, ranging from nearly 3000 for small-capacity, largely manually operated models to more than 10,000 for larger and more automated units. In addition to capacity, other cost features include the ability to vary heat and pressure cycles as well as different exhaust capabilities. Besides the cost for an autoclave, additional supplies necessary to operate the unit include trays, indicator tape that verihes sterilization parameters, autoclavable disposal bags, and gloves for handling hot containers. 

Steam is highly corrosive and wears out valves, seals, and other autoclave parts. Because of this problem, it is important to conduct a thorough inspection by a qualified technician at least once a year. 

Centrifuges vary in the number and volume of samples that can be run at one time as well as speed control options, timers, and temperature control. Benchtop clinical centrifuges capable of generating a relative centrifugal force of 3000 X g or greater range in cost from near 1500 to 

Far less expensive than the GasPak system are so-called candle jars. These are 1 gallon, wide-mouth glass jars equipped with tight-fitting lids. Once the Petri plates have been placed in the jar, a small candle is ignited. Upon sealing, the candle will burn until most of the O2 is consumed. 

Prior to pouring hot media to prepare either pour (Section 14.5.1) or spread plates (Section 14.5.2), it is necessary to equilibrate or temper the 

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Dryers. A drying operation (see Drying agents) needs to be viewed as both a separation and a heat-exchange step. When it is seen as a separation, the obvious perspective is to cut down the required work. This is accompHshed by mechanically squeezing out the water. The objective is to cut the moisture in the feed to the thermal operation to less than 10%. In terms of hardware, this requires centrifuges and filters, and may involve mechanical expression or a compressed air blow. In terms of process, it means big crystals. 

Beef muscle Homogenize, dilute with distilled water, centrifuge and filter to remove water-insoluble particulates extract onto solid-phase sorbents ITMS 50-100 ppb 20-50% Buchanan et al. 1995... 

The design, construction and application of thickeners, centrifuges and filters is a specialised subject, and firms who have expertise in these fields should be consulted when selecting and specifying equipment for new applications. Several specialist texts on the subject are available Svarovsky (2001), Ward (2000) and Wakeman and Tarleton (1998). The theory of sedimentation processes is covered in Volume 2, Chapter 5 and filtration in Chapter 7. 

Ionic mercury is extracted from about lg soil by shaking for 2h with each of two 25mL portions of 2M sodium chloride. The combined centrifuged and filtered (using 1M sodium chloride for washing) extract is analysed by the procedure of Polley and Miller [31]. 

The major contaminant is water, usually from leaks in the cooler. Demulsibility is, therefore, a factor. The centrifuges and filters generally employed take care of solids as well as water, but the major factor is the extremely long service life expected of turbine oil—50,000 to over 100,000 hours. Consequently, stability is of greatest importance. 

Tecator Ltd. [16] have described a flow injection analysis method for the determination of 0.2 -1.4 mg/1 (as NH3N) of ammonia nitrogen in soil samples extractable by 2 M potassium chloride. The soil suspension in 2 M potassium chloride is centrifuged and filtered and introduced into the flow injection system for the analysis of ammonia (and nitrate) one parameter at a time. Ammonia is determined by the gas diffusion principle, in which a PTFE membrane is mounted in the gas diffusion cell. 

The malt and soy wastes were prepared with 80 g of waste that was hydrolyzed with 1 L of 0.6 M HC1, which broke down various oligosaccharides into simple sugars such as glucose. The mixture was allowed to reach 121°C and was incubated for 30 min at evaluated pressure (1 kgf/cm2). The resultant mixture was neutralized by the NaOH pellet, centrifuged, and filtered. The hydrolyzed malt waste was diluted with a third volume of distilled water. 

The fish samples were deboned using a polyethylene knife. The vegetative samples and fish meat were digested in 5 M HNO at about 110-120 on tbe sand bath. This method was found to be convenient, rapid, with maximum metal extraction and minimum contamination possibilities. All the samples were centrifuged and filtered in the same way described earlier. 

The unripe apples were homogenized in potassium pyrosulfite solution, and the mixture was allowed to stand for 1 day. The supernatant was centrifuged and filtered with a glass filter funnel. The filtrate was apphed to adsorption chromatography, and the ACT fraction was evaporated and lyophilized. Purified ACTs were a mixture of monomer (catechin and/or epicatechin) and oligomers from dimers to pentadecamers, as shown in Fig. 2. 

The final validation test is done to demonstrate that no drug substance was lost from the extraction process, as this is a purity test. In a typical extraction process, as described above, the sample is crushed, extraction solvent is added, the sample is then stirred, sonicated, centrifuged, and filtered. In some cases, the drug substance will adhere to the filter. In this event, a study of numerous types of filters ensues to find one that yields 100% recovery. 

James K. McGillicuddy, B.S.M.E. Product Manager, Filtration Centrifuges and Filters,... 

One gram of tomato was extracted with 20 mL of 1 % acetic acid for 2 hr, centrifuged, and filtered. 

After centrifugation and filtering, the decanted liquid is analyzed for sulphates, nitrates and chlorides using ion chromatography. 

Gabl and Pastner (Gl) have analyzed the proteins in mixed saliva of 10 normal persons with paper and agar electrophoresis and ImEl. The saliva samples were first centrifuged and filtered later their protein concentration was increased to 1-B % by ultrafiltration under pressure. Whereas in paper and agar electrophoresis five fractions were separated, ImEl showed up to 9. These were in locations identical with those given... 

Sample preparation Ointment. Add pentane EtOH 75 25 to ointment, sonicate for 20 min, dilute an aliquot to 100 mL with MeOH, allow to settle. Centrifiige and filter an aliquot of the supernatant, inject an aliquot of the filtrate. Cream, lotion. Stir cream or lotion in EtOH THF water 25 25 50 at 40° for 15 min, cool in an ice bath. Centrifuge and filter an aliquot of the supernatant, inject an aliquot of the filtrate. Gel. Dissolve gel in EtOH, sonicate, filter, inject an ahquot. 

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