Long term storage stability

Solutions of hydrogen peroxide are of high purity, readily transportable in bulk quantities and exhibit long-term storage stability over a wide range of conditions. When stored in compatible vessels under ambient conditions and free from contamination, solutions of 35 %, 50 %, or 70 % H2O2 concentration will lose less than 1 % of their available oxygen content within a year. 

The structure of MAO is poorly defined and varies with preparation conditions, but it performs well in activating the metallocene initiator. The use of MAO is complicated by its lack of long-term storage stability. It is usually supplied by manufacturers as a cloudy solution of MAO in toluene MAO has very low solubility in aliphatic solvents. Precipitation is often observed on long standing, especially if the container is frequently opened and exposed to moisture and oxygen. This precipitation, if not too extensive, may not affect the utility of the MAO as a coinitiator. A modified MAO, known as MMAO, offers some improvement in storage stability and improved solubility in aliphatics. MMAO is prepared by controlled hydrolysis of a mixture of trimethylaluminum and triisobutylaluminum. 

This test method has been demonstrated to be effective for use in predicting the long-term storage stability of distillate fuel. The results obtained closely approximate those obtained after fuel storage at ambient temperature. For example, fuel storage at 110°F (43°C) for 12 to 13 weeks has been shown to correlate well with one year of storage at ambient temperature. 

Diesel-water emulsions are not approved for shipment by finished product pipeline companies. Consequently, the emulsion must be made on-site or near the point of sale. Other issues currently being resolved deal with improving the cold-temperature handling properties of the high-water-content fuel and improving the long-term storage stability of fuel blends... 

Long term storage stability tests of flavor beta-cyclodextrin complexes under "non-stress" conditions at room temperature showed that molecular encapsulation in most cases provided an almost perfect preservation of flavors upon ten years storage. The degree of preserving power of cyclodextrin complexation is expressed using a comparison of total flavor content of complexed flavor samples deteimined in 1977 and 1987,respectively./Table IV./... 

Bioanalytical method validation criteria should be applied to analytical methods whenever possible. It was also decided that long-term storage stability was not necessary, although short-term stability should be demonstrated. 

In this section, we discuss about the screen printed electrode (SPE) based AChE sensors for the selective determination of OP and CA pesticides. In the past decades, several attempts were made by the researchers to develop SPE based pesticide sensors, where the enzyme AChE was immobilized either directly onto the electrode or above other matrices incorporated SPE surfaces. Both approaches resulted in the good, rapid detection of OP and CA pesticides. Earlier, Hart et al. employed AChE/SPE to detect OP and CA pesticides [21], They measured the enzyme activity from the rate of hydrolysis of acetylthiocholine iodide. Three polymers such as hydroxyethyl cellulose, dimethylaminoethyl methacrylate, and polyethyleneimine were used as enzyme immobilization matrices. Initially, electrodes were exposed to drops of water or pesticide solution, dried and their activity was screened after 24 h. They found that, when the enzyme matrix was hydroxyethyl cellulose, electrode activity inhibited both by water as well as by pesticides. While with co-polymer matrix, a significant response towards pesticides alone was observed. Further, the long-term storage stability of electrodes was highest when the enzyme matrix consisted of the co-polymer. The electrodes retained their activity for nearly one year. In contrast, the electrodes made of hydroxyethyl cellulose or polyethyleneimine possess less stability. 

When long-term storage stability profiles become available, these profiles can be used to justify a reduction in the degradant peak set. The scientific rationale for this decision should be documented. 

Long-term storage stability in the biological matrix can be updated during in-study validation. 

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