Biocides, analysis

Aqueous GPC can also be semiprepped in manner just like nonaqueous GPC. In this case one must consider carefully the buffers, salts, and biocides used in the eluant. If the fractions are destined for nuclear magnetic resonance experiments it will be imperative to either reduce the salt concentration in the eluant or remove salt after the initial fractionation. Likewise, if the collected samples are destined for infrared (IR) analysis, it is important to choose salts and buffers that have good IR transparency in the wavenumber ranges of interest. 

Water quality is important, not only from an environmental point of view but also in relation to the type of packing to be specified. Analysis of the circulating water is simple to obtain, but it is very seldom offered to the cooling tower designer. The quality, or lack of it, will determine the type of pack to be used, the selection of structural materials and whether the tower should be induced or forced draft, counterflow or crossflow. Water treatment, in the shape of chemicals to control pH and to act as counter-corrosion agents or as biocides, all has a bearing on tower selection. 

API Serial Dilution Method. The API serial dilution method is the most widely used method for the detection of microorganisms. Field test methods for estimating bacterial populations have been standardized. A standard method dealing with the dose-response (time-kill) testing for evaluating biocides has been established. Sampling methods are of special importance because effective sampling is essential to any successful analysis. 

Biocides Reporting Service provides monthly information on biocides and end-user industries through the world. The information searches are tailored to individual business needs and sent to key members of that company. The information is sourced from over 200 worldwide trade journals and covers competitors, customers, industry analysis trends, regulations and patents. 

SFE has been used extensively in the analysis of solid polymers. Supercritical fluid extraction of liquid samples is undertaken less widely because dissolution or entrainment of the matrix can occur. As illustrated elsewhere SFE has also been applied for the analysis of liquid poly(alkylene glycol) (PAG) lubricants and sorbitan ester formulations [370]. The analysis of PAG additives (antioxidants, biocides and anticorrosion, antiwear and antifoaming agents) is hindered by the presence of the low molecular weight PAG matrix (liquid) and therefore a method for the selective separation of additives from PAG is required. The PAG... 

The Swedish Chemical Inspectorate (KEMI) has used substitution analysis to assess biocides with the goal of promoting sustainable agriculture. KEMI uses a seven-step process that evaluates not only the intrinsic... 

Acidification to below pH2 is particularly suitable for trace metals since it minimises adsorption of metals to container walls and also reduces biological activity. Acidification before filtration will release metals bound to particulates, giving a false reading only if dissolved metals are required. Samples for anion analysis are generally not acidified. Biocides such as sodium azide are commonly added to samples... 

Ferrario D, Rabbit RR (2012) Analysis of the proposed EU regulation concerning biocide products and its opportunities for alternative approaches and a toxicology for the 21st century (t4 report). ALTEX 29 157-172... 

The biocidal activities of a series of quatemised PUs were examined a inst Staphylococcus aureus and E.coli. The effect of quatemisation on material properties was examined with tensile testing, water absorption analysis, and contact angle measurements. The antibacterial action of the polymers was investigated. 19 refs. 

After adsorption of the biocides, these have to be desorbed and made accessible to analysis. For desorption from PUF the Soxhlet extraction is commonly used. As alternatives supercritical fluid extraction (SFE) with COj and elution with different solvents were tested. 

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