Laboratory screening procedures for

This Draft International Standard, circulated in May 1990, specifies a small-scale laboratory screening procedure for comparing the relative burning behaviour of vertically or horizontally oriented plastic specimens exposed to a low-energy ignition. It covers rigid solid or cellular plastics having an apparent density of not less than 250 kg/m, determined in accordance with ISO 845. 

This Draft International Standard, circulated in March 1990, specifies a small-scale laboratory screening procedure for comparing the relative burning characteristics and resistance to penetration by the... 

This test covers a small-scale laboratory screening procedure for measuring the rate of burning and/or extent and time of burning of rigid or flexible cellular plastics. It was discontinued in 1978 and has not been replaced. 

Mills, W.B., Dean, J.D., Porcella, D.B., Gherini, S.A., Hudson, R.J.M., Frick, W.E., Rupp, G.L., Bowie, G.L. (1982) Water Quality Assessment A Screening Procedure for Toxic and Conventional Pollutants. EPA-600/6-82-004a, Environmental Research Laboratory, Environmental Protection Agency, Athens, Georgia. 

In the authors and several other OPCW-designa-ted laboratories, LC/MS is used as the initial screening procedure for water samples and aqueous extracts of matrices such as soil. This usually provides a tentative identihcation of polar analytes within half a day, on the basis of molecular mass, any fragment ions present, and retention time. A second analysis, under LC/MS/MS conditions, usually provides a firmer identihcation on the basis of a limited number of product ions, most of which result from simple neutral losses. With clean matrices, the initial screening may be performed even faster using how injection or infusion rather than LC (14). An example of the application of how injection with electrospray ionization/mass spectrometry (ESI/MS) in an OPCW prohciency test is provided by Hooijschuur et al. (21) The identihcation of the analytes is usually conhrmed by GC/MS (in most cases after derivatization) as the second technique. 

LC/MS is an important addition to the techniques used routinely to analyze unknown samples. It is not a substitute for other techniques but is complementary, for example, to GC/MS, GC/FTIR, and NMR. In OPCW proficiency tests, a number of laboratories use single-stage LC/MS as a rapid screening procedure for water samples and aqueous extracts of matrices such as soil, and GC/FPD or... 

In areas that have experienced a yellow rain attack, environmental assays have been in the range of 1 to 150 parts per million (ppm) and blood samples in the range of 1 to 296 parts per billion (ppb).8"1016 22 In the laboratory, at 10 and 50 minutes after an intramuscular exposure to 0.4 mg/kg of T-2 toxin in the dog, plasma concentrations of T-2 toxin were 150 and 25 ppb, and for HT-2 toxin were 50 and 75 ppb, respectively.60 Thus, any screening procedure for trichothecene mycotoxins in biomedical samples must have detection limits of 1 to 100 ppb. Most of the analytical procedures require extraction and cleanup treatment to remove interfering substances.73... 

The evaluation of a number of immunoassay diagnostic kits was undertaken to determine their usefulness in a regulatory analytical laboratory environment in the food, feed and pesticide areas. Four rapid enzyme immunoassay tests for the detection of aflatoxin residues at the 20 ppb level in animal feeds were compared to the official HPLC procedure. In the pesticide area, a commercial pentachlorophenol competitive inhibition assay for residues in water was investigated as to its applicability to poultry and pork liver matrices. In addition, an ELISA screening procedure for the herbicide fusilade was developed. Modifications were incorporated into the rapid immunoband 1-2 Test procedure for the detection of motile Salmonella in various food and animal feed products resulting in quicker analysis than the standard culture method. Also, a comparative evaluation of a Quik-Card Test for sulphamethazine drug residues in pork urine, liver and muscle tissue, is described. 

Comprehensive Gas Chromatographic Drug Screening Procedures for the Clinical Laboratory Clin. Biochem. 6(2) 124-131 (1973) ... 

Mills WB, Dean JD, Porcella DB, Gherina JA, Hudson RJM, Frick WE, Rupp GL, Bowie GL (1982) Water quality assessment a screening procedure for toxic and conventional pollutants. EPA 600/6-82-004a, Environmental Research Laboratory, Athens, GA. 

Of the methods developed for the identification of hydrocarbon mixtures, only coupled gas chromatography-mass spectrometry holds any real promise of certain identification and this only at a prohibitive cost in time spent characterising minor peaks. It would be far more efficient to develop rapid screening procedures which would eliminate all but a few possibilities, and then use gas chromatography-mass spectrometry to isolate and identify a few key peaks to confirm the characterisation. This is precisely the scheme adopted independently by a number of laboratories. 

In New York and Massachusetts where PCB contamination is always a possibility, the laboratory tests required by the state environmental protection agencies for analysis of a petroleum-contaminated soil are as follows (a) flash point (b) total petroleum hydrocarbon (TPH) (c) PCB screening (d) total organic halides (TOH) (e) reactivity of cyanide and sulfide (f) BTEX or equivalent (g) eight metals under TCLP (Toxicity Characteristics Leaching Procedure) for USTs and (h) full range of tests under TCLP for ASTs and spills. 

For lack of an acceptable routine procedure for the direct assessment of ciguatoxin in fish tissues, the mouse bioassay with extracted lipids remains the method of choice for most laboratories doing ciguatoxin research. In addition, the radioimmunoassay has proven of value in screening S. dumerili (22, 23), but it is precluded for routine screening because of its cost factor and technical procedure. Nevertheless, it has been of value in the survey and assessment of new fishing grounds (28). 

U.S. Environmental Protection Agency, Sampling and Analysis Procedures for Screening of Industrial Effluents for Priority Pollutants. Method 610, Polynuclear Aromatic Hydrocarbons, Environmental Monitoring and Support Laboratories, Cincinnati, OH, 1977. 

Several different experimental conditions are used, depending on the laboratory, without any consensus agreement on which of these should be used for screening. This in part renders difficult comparison of results between laboratories. However, whatever the recipes used, one has to fully understand the complex regulatory properties of each of these activities before proceeding. These are presented below for each MRC complex routinely measured in the context of screening procedures. It is preferable to use a (pseudo-)double-wavelength spectrophotometer, since such a machine can now be obtained at a reasonable price and results in better, more... 

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