Overall Rapid extraction test

Packaging Technology and Science 10, No.3, May-June 1997, p.169-75 PVC THERMOFORMED CONTAINERS FOR FOOD PACKAGING ESTABLISHMENT OF RAPID EXTRACTION TEST FOR OVERALL MIGRATION LIMIT COMPLIANCE TESTING Cooper I Goodson A Tice P A PIRA International... 

The cell-bound amylopullulanase was solubilized with detergent and lipase. It was then purified to homogeneity by treatment with streptomycin sulfate and ammonium sulfate, and by DEAE-Sephacel, octyl-Sepharose and puUulan-Sepharose column chromatography (12). The final enzyme solution was purified 3511-fold over the crude enzyme extract with an overall recovery of 42% and had a specific activity of 481 units/mg protein. The average molecular weight of the enzyme was 136,500 determined by gel filtration on Sephacryl S-200 and SDS-PAGE, and it had an isoelectric point at pH 5.9. It was rich in acidic and hydrophobic amino acids. The purified enzyme was quite thermostable in the absence of substrate even up to 90°C with essentially no loss of activity in 30 min. However, the enzyme lost about 40% of its original activity at 95 C tested for 30 min. The optimum tenq)erature for the action of the purified enzyme on pullulan was 90°C. However, the enzyme activity rapidly decreased on incubation at 95°C to only 38% of the maximal 30 min. The enzyme was stable at pH 3.0-5.0 and was optimally active at pH 5.5. It produced only maltotriose and no panose or isopanose from pullulan. 

The assessment can also be done by an off-line SPE procedure where the cumulative recovery curves of the sorbents are evaluated in different solvents and at different pHs. A suitability test for propranolol imprinted sorbents, to be used in SPE of plasma and urine samples, was developed by Olsen et al. [34]. This was based on the solvent composition required to give a recovery of either 20 or 50% of the extracted material (ES20 or ES50 values) on the blank and the imprinted cartridge. The method was developed in order to allow a rapid estimate of the specific and non-specific contributions to overall binding. 

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