Tests organic residues

Inorganic cations, although probably isolated by ion exchange, should not be soluble in the dichloromethane extract of the aqueous eluents and should probably remain therein. The experiment with lead(II) nitrate, which yielded <0.2 of the spiked Pb ion, supported this expectation. Therefore, heavy metal toxicity to bioassay systems should not be a problem for testing organic residues. Conversely, when inclusion of inorganics in a test residue is desirable, other recovery techniques should be considered. 

The preferred method of determining water in glycerol is by the Kad Fischer volumetric method (18). Water can also be determined by a special quantitative distillation in which the distilled water is absorbed by anhydrous magnesium perchlorate (19). Other tests such as ash, alkalinity or acidity, sodium chloride, and total organic residue are included in AOCS methods (13,16,18). 

Several reactivation routes of the used catalyst were tested such as dissolution of organic residues by dichloromethane or burning of them by heating in air. In this way, initial activity was recovered, thus regaining complete conversion. 

The residue is removed from the leaf surface by shaking the leaf punch sample in an aqueous surfactant solution. This allows for removal of test substance residue from the leaf surface. It does not remove residue absorbed on the plant matrix that extraction and maceration in organic solvents would release. Generally, the extraction with aqueous surfactant is performed using a mechanical shaker for a 10-min interval and is repeated to increase transfer efficiency. 

Bio-Electrics, Incorporated, has developed the Electrofrac Detoxification System to treat hazardous contaminants in soil. The system, which was developed from gasification research, uses electrodes placed in soil to heat the site. There are potential applications of this technology for removal of volatile organic compounds (VOCs), pyrolysis of non-VOCs, treatment of organic residues, and in situ vitrification of soils and asbestos. There have been bench-scale tests of the technology for remediation applications. 

Failing to test for residues of organic or inorganic solvents that may carry over to the API. 

The ATP test is a bioluminescence procedure based on the reaction between adenosine-5-triphosphate (ATP) and a luciferin-luciferase enzymatic system (42, 43). The principle of the test relies on the fact that after a certain incubation period the intracellular ATP level, which gives a reliable indication of the state of development of a suitable bacterial culture (44), will remain low relative to a control, when antimicrobial residues are present. In its first version the ATP test employed Bacillus subtilis ATCC 6633 as the test organism, but a current version is based on the use of Streptococcus thermophilus T.J. culture. 

Since 1974, Bacillus subtilis EGA has been officially employed as the test organism in the German Hemmstoff test to detect residues of tetracyclines, -lactams and aminoglycosides in kidney and muscle tissues with high sensitivity (72). Macrolides can be also detected, but to a lesser extent, whereas chloramphenicol and sulfonamides are difficult to detect. For better detection of sulfonamides, a modification of this test, the German three-plate inhibition test, was developed. This test is based on the same test organism but uses three pH values (6, 8, and 7.2), with the addition of trimethoprim. The pH relationship between the three... 

Initial studies on sulfonamides (114) were limited to qualitative assessment of the occurrence of sulfamerazine residues in muscle and interior organs of rainbow trout using Sarcina lutea (ATCC 9341) and Staphylococcus aureus (ATCC 6538P) as test organisms. The method involved application of fish fluids... 

Ampicillin residues in cultured fish muscle have been detected by a disk diffusion assay using Bacillus stearothermophilus (ATCC 10149) as the test organism (125). In this method, fish sample was homogenized with phosphate buffer, pH 6.0, and centrifuged. The supernate was heated at 82 C for 2 min, and analyzed according to the AOAC assay including the confirmatory -lactamase step. Recoveries of ampicillin ranged from 99 to 104%, whereas the limit of determination was 0.025-1.00 g/g. This method has also been successfully applied for the determination of amoxicillin residues in catfish muscle (126). 

Chemical and biological analyses of trace organic mixtures in aqueous environmental samples typically require that some type of isolation-concentration method be used prior to testing these residues the inclusion of bioassay in a testing scheme often dictates that large sample volumes (20-500 L) be processed. Discrete chemical analysis only requires demonstration that the isolation technique yields the desired compounds with known precision. However, chemical and/or toxicological characterization of the chemical continuum of molecular properties represented by the unknown mixtures of organics in environmental samples adds an extra dimension of the ideal isolation technique ... 

Chemistry support is frequently needed to measure the residues of possible toxic substances such as pesticides in each lot of test organisms before they are used in toxicity tests. The analysis should be extensive enough that the data will document any residues that might interfere with the usefulness of the test. 

Inspectors and quality assurance personnel should routinely ask to see the chemical analyses or residue analyses performed on each lot of test organisms used in bioassays that were reported to the Agency. 

If the test organisms were fed while in the laboratory, the data base for the study should include documentation that the food was free of residues of chemicals that could adversely affect the results of the test. There should be a complete record of these analyses in the archives. 

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