Sample Preparation - UniSolv references and leaching LDPE bottles
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admin
Total posts: 529
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The techniques described were developed by Dr. Paul Gaines as part of the proprietary UniSolv process for analyzing zeolites, and no peer-reviewed reference was published. If a reference is required, we would suggest the “(P. Gaines, personal communication)” approach often cited in research literature. As for the bottles, LDPE bottles are catalyst-free whereas HDPE can contain catalyst residue, so if you use LDPE from Nalgene there should be no concerns. Regarding the HF leach concentration, we've used 0.1M HF (~0.3% v/v) mixed with 0.5M HNO3 (~3% v/v) at 60 °C for 60 hours to clean a variety of plastics (LDPE, HDPE, and polypropylene) and had good results . This or a similar approach should be suitable for your application.
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admin
Total posts: 529
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The use of triethanolamine (TEA) and EDTA to neutralize and stabilize acidic metal solutions was developed as part of our UniSolv process for zeolite determinations (https://www.inorganicventures.com/elemental-analysis-zeolites), and grew out of our own research initiatives. As a result, we reference no peer-reviewed literature sources specific for our application, but the use of TEA and EDTA in titrimetric methods for metals is well documented, and that is where much of the background information we built upon may be found. One good reference for that information is “The Analytical Uses of Ethylenediaminetetraacetic Acid” by F.J. Welcher (1958). As for the bottle choice, Nalgene LDPE is a great material, and should not contain any catalyst residues, which are more of a concern with HDPE due to differences in the polymerization process. For cleaning purposes, dilute HF refers to a solution of ~0.1 – 0.5% (v/v) HF. Lower acid concentrations can be as effective for cleaining/leaching plastics as higher acid concentrations, but usually longer leach times are necessary. |