Contamination avoidance procedures

In conclusion, it is my opinion that the laboratory results should not be considered in isolation but should be interpreted with the knowledge that established and reliable contamination avoidance procedures are in operation and that they are monitored on a regular basis. 

During this time he experienced many complex and controversial cases, the vast majority of which were terrorist-related incidents. His main interests include the chemical examinations relating to firearms casework, research and development work arising from same, crime scene examination, health and safety issues, quality assurance, suspect handling and processing, and contamination avoidance procedures both inside and outside the laboratory. 

Equipment and supplies should be placed in the enclosure before a contaminant-generating procedure commences. Unnecessary equipment should be removed. High-input heat sources within an enclosure will cause convection currents that can disturb the flow and should be avoided, if possible, or accounted for with correct placement of baffles and/or exhaust connections. 

Improve suspect processing procedures and contamination avoidance measures. 

In order to avoid this contamination, the procedure described herein utilizes a somewhat higher temperature and a lower concentration of ammonia than has previously been suggested. " The formation of the pink precipitate of hexaamminecobalt(II) chloride is thereby completely eliminated. An additional advantage of the procedure is that no special apparatus is required. - - ... 

Healthcare providers, as well as local officials, are concerned about the spread of contamination. The procedure for decontamination of litter patients can be found in Appendix E of U.S. Army Field Manual 8-10-4, Medical Platoon Leaders Handbook Tactics, Techniques and Procedures.8 The IRF will decontaminate patients and pass them across a hotline to the Medical Response Team (MRT). At that point the casualty should be completely clean. Civilian officials may require a casualty certified clean before moving the patient off the military installation. This requirement may be avoided through adequate coordination and training prior to an exercise or an actual chemical accident or incident. Building confidence in the civilian sector through education and communication is essential in providing a rapid and adequate medical response. 

In earlier procedures, the ReO anion was precipitated from water as the relatively insoluble potassium salt. Reduction of KReO with hydrogen gas gives rhenium metal, but the metal is contaminated with ca 0.4 wt % potassium that cannot be separated easily. Although suitable for some purposes, rhenium formed from KReO is found to be unsatisfactory in appHcations such as those for use in filaments in mass spectrometer systems. The route involving NH ReO avoids this problem. 

Pretreatment For most membrane applications, particularly for RO and NF, pretreatment of the feed is essential. If pretreatment is inadequate, success will be transient. For most applications, pretreatment is location specific. Well water is easier to treat than surface water and that is particularly true for sea wells. A reducing (anaerobic) environment is preferred. If heavy metals are present in the feed even in small amounts, they may catalyze membrane degradation. If surface sources are treated, chlorination followed by thorough dechlorination is required for high-performance membranes [Riley in Baker et al., op. cit., p. 5-29]. It is normal to adjust pH and add antisealants to prevent deposition of carbonates and siillates on the membrane. Iron can be a major problem, and equipment selection to avoid iron contamination is required. Freshly precipitated iron oxide fouls membranes and reqiiires an expensive cleaning procedure to remove. Humic acid is another foulant, and if it is present, conventional flocculation and filtration are normally used to remove it. The same treatment is appropriate for other colloidal materials. Ultrafiltration or microfiltration are excellent pretreatments, but in general they are... 

Shared equipment Design to avoid or minimize use of (e.g. auxiliary process- common equipment for incompatible ing scrubbers ). Pos- materials sihility of incompatible, Implement proper cleaning procedure materials coming between incompatible uses to prevent together. cross contamination Prescrub or treat process streams before transfer to common equipment API RP 750 CCPS G-11 CCPS G-22 Kletz 1991 Lees 1996 NFPA-91... 

The use of a 0.5 molar excess of pyridine and fcrt-butyl alcohol is necessary in this case to obtain a satisfactory yield. However, when this procedure is applied to preparation of other alkoxycarbonates (Table II), an excess of the alcohol should be avoided since it may contaminate the product. 

Because plants present chlorophylls and carotenoids simultaneously, it may be useful to separate both groups from each other in a laboratory or preparative scale in order to avoid contamination in further purification steps, mainly when they are prepared in large amounts. Clean-up procedures using an open column packed with absorbents such as alumina, magnesia, polyethylene powder, powdered sucrose, DEAE-Sepharose, starch, cellulose, or MgO HyfloSupercel are good approaches. MgO HyfloSupercel in a proportion of 1 1 or 1 2 is the usual adsorbent. Sucrose and cellulose are interesting as they do not alter the chlorophylls, but they are tedious to work with. 

The analytical procedure is checked by analyses of method blanlcs to assure that secondary contamination by the analytes to be determined is avoided or minimized. Because the water content of the CRM matrix to be analyzed may vary from one laboratory to another (dependent on the local humidity and temperature), the water content has to be determined. Accordingly, at least three independent samples are kept at I05°C for 2 h, then allowed to cool to ambient temperature in a desiccator and the water loss is determined. The certified values are generally reported on a dry mass basis. 

For stone fmit, e.g., olive cherries, where the mature fruit is analyzed, the stone should be removed, and the weight of pulp and stone should be recorded. The residue is calculated on the basis of whole fruit. This step can be done either in the field prior to the fruit being frozen, which makes the procedure easier, or in the analytical laboratory. In either case, care needs to be taken to avoid cross-contamination. 

Foot exposure of workers can be measured by using socks as dosimeters or anklet dosimeters worn under ordinary socks. Usually an ordinary sock or anklet bought at a retail store will suffice for the dosimeter. As with whole-body dosimeters, the sock material should be 100% cotton but may be other materials. Pre-washing the socks or anklets prior to use in the field may be necessary if analytical interferences are found in the sock material. The socks or anklets should be put on the volunteer using procedures similar to those already described in order to avoid cross-contamination of the sock dosimeter. 

Batch reactors are often used for liquid phase reactions, particularly when the required production is small. They are seldom employed on a commercial scale for gas-phase reactions because the quantity of product that can be produced in reasonably sized reactors is small. Batch reactors are well suited for producing small quantities of material or for producing several different products from one piece of equipment. Consequently they find extensive use in the pharmaceutical and dyestuff industries and in the production of certain specialty chemicals where such flexibility is desired. When rapid fouling is encountered or contamination of fermentation cultures is to be avoided, batch operation is preferable to continuous processing because it facilitates the necessary cleaning and sanitation procedures. 

Succinic anhydride is dimerised to 1,6-dioxaspiro [4.4] nonane-2,7-dione by heating with sodium hydroxide. Modification of an existing procedure by adding further sodium hydroxide after the initial reaction led to a severe exothermic reaction after heating for some 30 h which fused the glass flask to the heating mantle, probably at a temperature approaching 550°C. The reason for this was not known [1], At elevated temperatures and under influence of alkali, succinic acid condenses decarboxylatively beyond the dimeric spiroacetal, sometimes explosively. Contamination of the anhydride with base is to be avoided [2],... 

However, pyrolysis is rapid, avoids sample wet chemical workup, avoiding sample loss and contamination, and has a low sample requirement. It allows the determination, in a single step, of polymeric materials (with in situ hydrolysis of the hydrolysable polymers and thermal decomposition of the nonhydrolysable polymers) and low molecular weight components [16]. As a result, pyrolysis is a relatively fast and inexpensive technique, especially if compared with the classical wet analytical procedures that are required prior to GC/MS analyses. 

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