Preservative requirements

Unless your customer has specified packaging requirements, there are several national standards that can be used to select the appropriate packaging, marking, and preservation requirements for your products. Your procedures should make provision for the selection to be made by qualified personnel at the planning stage and for the requirements thus selected to be specified in the packing instructions to ensure their implementation. 

The influence of pH, Emulsifier, and Accelerated Ageing upon Preservative Requirements of O/W Emulsions, by Gene Jacobs, M.S. at all Soc. Cosmet. Chem., 26,105-117 (February, 1975)... 

This preservation requires that k l 1. It could be accomplished by changing the fuel in the model to one that would yield more soot. This may not be done with great accuracy, but is feasible. 

Although these methods measure different petroleum hydrocarbon categories, there are several basic steps that are common to the analytical processes for all methods, no matter the method type or the environmental matrix. In general, these steps are (1) collection and preservation—requirements specific to environmental matrix and analytes of interest (2) extraction so that separations of the analytes... 

Short-term preservation (several weeks) can usually be successfully accomplished by generous application of polyethylene plastic wrap and duct-tape. Be careful in applying the tape to avoid direct contact with the items. The adhesive can be left behind on the part and when removed, can take with it important dust, fibers, or other data. Even short-term preservation requires some control of access, chain of custody documentation and conspicuously posted signs. Many workers are genuinely curious to learn and see for themselves what the damaged or essential part actually looks like, and may unintentionally cause changes. 

Every analytical method has its own container and preservation requirements for each matrix. Containers for water samples that are precleaned and preserved with chemicals according to the EPA protocols are available from various manufacturers. We may also obtain them from the laboratory, which will provide analytical services for the project. The container cleanliness and the purity of preservation chemicals must be of the highest quality in order not to introduce any extraneous contamination into the samples. 

Unfiltered and unpreserved groundwater water samples collected for total and dissolved metal analyses arrived to the laboratory in a cooler with ice three days after collection. On the fourth day after collection the laboratory filtered the samples for dissolved metal analysis and preserved all samples with nitric acid. The violation of the preservation requirements (no acid ice instead of ambient storage temperature) had a marginal effect on the concentrations of total metals as the addition of acid dissolved most of the metals that may have precipitated in the sample container. That is why the chemist accepts the total metal results, but qualifies them as estimated data. However, because improper preservation and storage have grossly compromised dissolved metal concentrations, the chemist rejects the dissolved metal results and requests that the water be resampled and reanalyzed. 

Function Antioxidant bleaching agent preservative. REQUIREMENTS... 

By knowing the concentration of preservative required for the necessary biological effect in the aqueous phase (Cw), the oil water phase ratio (6) and the for the system, C, the concentration needed inthe formulation, may be calculated from the expression... 

A stable floe may also be produced by dispersing insoluble particles in a turbid or hazy vehicle consisting of finely dispersed or emulsified semipolar, liquid droplets, which cause the droplets to be adsorbed on the surface of the insoluble drug particles, resulting in a stable floe. Turbid aqueous vehicles have been prepared by the interaction of non-ionic surfactants and preservatives. The concentration of surfactant and preservative required for haze formation may be reduced by the addition of small amounts of sorbitol to the vehicle. 

Kurup TRR, Wan LSC, Chan LW. Preservative requirements in emulsions. Pharma Acta Helv 1992 67 204-208. 

Jacobs G, Henry SM, Cotty VF. The influence of pH, emulsifier, and accelerated ageing upon preservative requirements of o/w emulsions. / Soc Cosmet Chem 1975 26 105-117. 

Proteins are readily hydrolysed by microbial enzymes, and their preservation requires desiccation, freezing or pickling, to retard microbial action. The key degradation step is peptide-bond hydrolysis, which is temperature dependent. The more highly ordered and cross-linked proteins—such as keratin, fibrinogen (in silk and mollusc-shell matrix) and collagen (comprising... 

Water samples Water can be analyzed for a number of analytes, therefore, the storage conditions and preservatives required can vary. As some changes in samples can occur, certain physical and chemical measurements (temperature, pH value, alkalinity, conductivity, dissolved gases, etc.) are best carried out at the site of sampling to ensure accurate values. 

Water samples are usually refrigerated at 4°C for transport to the laboratory and in storage pending analysis. In addition, the sample preservation required depends on the stability of individual analytes. When sample preservation is required there are a number of possible approaches. The pH value of the nonchlorinated water samples can be adjusted by acidification to prevent bacterial growth, biological degradation, or retard acid or base catalyzed decomposition. 

The micromixer-based continuous formation of a hydrophflic cream for dermal application was studied by Schiewe et al. [16]. In addition to showing the feasibility and exploring the advantages compared with a conventional laboratory shaker, the investigations also targeted lowering the amount of emulsifiers and preservatives required since they can be the source of allergic reactions. 

Safety and hygiene effects. Limitations related to process/product safety can in some cases be solved by the use of microstructured reactors. For example, very exothermic reactions and explosive gas mbctures have been demonstrated to operate safely in structured reactors [12]. The transport of hazardous chemicals could also find sustainable solutions in the development of distributed production in miniaturized plants [13]. In the frame of product engineering, micromixers allowed the quantity of emulsifiers and preservatives required to stabilize emulsions for pharmaceutical applications to be reduced [14]. 

Susceptible to microbial attack. Preservation required Regulatory Status 21CFR 172.695, Food Chemicals Codex and National Formulary. TSCA registered. CAS No. 11138-66-2... 

Microbial Considerations Preservation required in contact with water. 515, 525, 526 stable as supplied. XL- 19X2, XL-28 are preserved with Dowicil 200. XL-40 is preserved with methylpara-ben plus propylparaben Supplier BF Goodrich... 

Microbial Considerations Resists bacterial attack and does not support mold growth. Preservation required for other components in the final formulation and for dispersions that will be stored for several weeks... 

Several preservative systems have been developed for NR latex to suppress the proliferation of bacteria. Ammonia is the most common preservative used for NR field latex. It is a known mild bactericide and also functions as an alkali to increase the pH of the latex. The normal practice is to add some ammonia to the field latex upon arrival at the factory to prevent auto-coagulation before further treatment. Since the field latex contains only about 30% solids, it is unsuitable for most technical appKcations. Thus field latex needs to be further preserved, purified and concentrated to about 60% sohds in many commercial technical grade latex concentrates. Long-term preservation requires strong preservatives and/or higher dosages of these. Latex concentrate is preserved usually with about 0.7% of ammonia at a pH of about 10.5. This is known as HA latex concentrate. Alternatively a low ammonia concentration of 0.2% is used in conjunction with tetramethylthiuram disulfide (TDTM) as copreservative. This latex concentrate, known as LA-TZ, contains 0.025% TMTD/ZnO and 0.05% ammonium laurate. HA and LA-TZ latex concentrates are the two most common latex concentrates marketed. 

Different film preservation requirements are also related to local painting habits. While the home owners in some South American countries are used to repaint their homes after two seasons latest, they do not need a film preservation for more than only 2 years. In Germany the thick coatings on EIFS are warranted by the producer for five years minimum, and customers expectations to have a clean wall are going even far beyond this period. Here, of course, more enthusiasm has to be put into the film preservation. In the tropical countries colonization of unprotected walls is that fast, that a very efficient broad spectrum film preservative is a must, because walls cannot be kept dry in this climate. 

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