Respirometric method

An attempt to automate the turbidi-metric method for the determination of neomycin with K. pne.umon4.ae. has been reported by Gerke et al281 who obtained satisfactory assays with solutions containing 150-1200 yg/ml of neomycin. An automated respirometric method, which measured the amount of CO2 produced by interaction of antibiotic and the bacteria E.cot.i was also reported with a similar sensitivity. In both methods Auto Analyzer systems were employed. 

With the organism grown in this manner the sensitivity of the assay is improved. Greely et al2 2 have applied the automated respirometric method to the determination of neomycin in pharmaceutical products and compared these assays with the results obtained by the cylinder-plate procedure on the same samples. Good correlation between the two procedures was demonstrated. 

HISSETT, R., EVANS, M.R. BAINES, S. 1975 The use of respirometric methods for assessing the biodegradability of different components of agricultural wastes. Progress in Water Technology 7(2) 13-21. 

Five-Day BOD test, ultimate BOD test, respirometric method Reflux method, titrimetric, colorimetric... 

ENISO 14851 2004 Aqueous Not exceeding six months Preferably between 20and25 Aniline, microcrystalline cellulose powder, ashless cellulose filters or poly-(3-hydroxybutyrate as positive reference Oxygen consumption (by, for example, respirometric method or measurements of changes in volume or pressure)... 

The respirometric method meastues either CO2 produced or CO2 constuned or both of them in an enclosed system with proper maintenance or regulation of air or oxygen supply. This technique is especially suitable for confirmation on the extent of mineralization It can be used for measuring degradation of soluble powder from fragile pofymeric materials. This method is easily adapted to a whole range of envirorunental conditions and/or specified or mixed culture microorganisms. 

The extent of biodegradation is usually measured using respirometric methods, which detect CO2 evolution. Other parameters to assess are the rate of MW loss, the loss of polymer physical properties (e.g., tensile strength per ASTM standard D3826-98 [5]), the rate of increase of the microbial culture colony size in contact with the material, O2 uptake (e.g., biochemical oxygen demand) and radioactive tracer techniques that use labelling. 

Respirometric methods can be classified into a number of basic measurement principles depending on two criteria (i) The phase where oxygen is measured (gas or liquid) and (ii) the flow regime of bofh gas and liquid phase, which can be either flowing or static [4]. From these criteria the modalities are... 

Reuschenbach, P. Pagga, U. Strotmann, U. A critical comparison of respirometric biodegradation tests based on OECD 301 and related test methods. Water Res. 2003, 37, 1571-1582. 

Tabak, H. H. Govind, R. (1993). Development of nonlinear group contribution method for prediction of biodegradation kinetics from respirometrically derived kinetic data. In Emerging Technologies in Hazardous Waste Management III, ed. D. W. Tedder F. G. Pohland, ACS Symposium Series 518, pp. 159-90. Washington, DC American Chemical Society. 

State of the polymer (visual assessment, calculation of the loss of mass, tensile testing, etc.) compared with the samples on the non-inoculated and the sterile media (Fignre 14.6). This strictly empirical method was not intended to show the biodegradability of materials in contact. The norm NF EN ISO 846 describes this methodology, but these kinds of tests are insufficient to show the biodegradability of the tested material, as they are too prone to subjective interpretation. However, they can be useful to show and reinforce other types of tests (particnlarly respirometric). 

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