Manufacturers of SPE products

Finally, on-line SPE has become routine for HPLC and is beginning to become more commonplace for GC/MS (Barcelo and Hennion, 1995 Brinkman, 1995). The latest trends in SPE are toward the use of disks and microfibers and the automation of many of the SPE products. Finally, there continue to be new manufacturers of SPE products, as well as a continued expansion of new packing materials and even wider applications for SPE. 

It is quite important to know the pore size of the silica gel (which controls surface area), the amount of liquid phase or functional groups bonded to the silica, the type of derivatization reagent (mono- or trifunctional), and the extent of endcapping. This information was realized by some of the manufacturers of SPE products thus, they supply customers with quality control and quality assurance (QA) data of their SPE products. Figure 2.8 shows an example of such a QA report from 1ST (International Sorbent Technology). 

Thurman and Mills [75] point out that knowing the analyte structure is the clue to effective isolation by SPE. A sorbent selection chart (Figure 2.34) is a useful guide for matching the analyte with the appropriate sorbent. Most manufacturers of SPE sorbents provide such guidelines either in printed product literature or on the Internet. To use a sorbent selection scheme, the analyst must be prepared to answer the following questions ... 

Surprisingly, the development of SPE procedures for fractionation of lipid samples has attracted relatively little attention as compared to conventional methods, such as TLC. However, because of its qualities and advantages, it promises to be applied much more in the future. The development of such separation methods is stiU in progress, as new sorbents and enhanced quality of packing will become available in the near future, from the more than 50 manufacturers currently making SPE products [9]. 

As a result of the variety of sorbents and manufacturers, the choice of sorbents at first appears complicated and perhaps overwhelming. However, many of the sorbents are similar, and the details of these sorbents, such as endcapping and percent carbon loading, are discussed in this book so that correct choices may be easily made. For example. Chapters 3 through 6 will explore the variety of sorbents and how to make informed decisions for many applica-. tions of SPE. Many of the chapters will give detailed product information on... 

Other information on-line for SPE is a number of vendors who provide information on their products, as well as on various applications of SPE. In fact, the worldwide web is an excellent place to find out the latest information on chromatography and SPE products. Nearly all of the major manufacturers of instrumentation have their hardware in photograph and diagram form on the web. Prices are often available as well. This section of the Appendix discusses the current web sites that were located using the search code solid phase extraction as well as looking up the specific vendors cited for their information on web solid-phase extraction. 

Summaries of the properties of both classical artd modem sorbents and their applications in high- and low-volume extractions of surface waters are foimd in Refs. [68,69]. Novel SPE products with application in surface water sampling will continue into the future, and detailed information concerning these as well as existing sorbents can be sourced from manufacturers. 

Collins has spent 30 years in the plastics industry, most notably with Premix in North Kingsville, Ohio where he served in various capacities including Sales Management, VP Product Engineering, VP Corporate Purchasing, and VP Manufacturing Operations. He has been an active member of SPE since... 

Not surprisingly, quality of the botanical products is a frequent review issue in our regulatory experiences. Some sponsors had not presented accurate name/identification of the botanical plants and/or description of manufacturing processes. Because of the recent incidence of diethylstilbestrol containing PC-SPES, adulteration of botanicals with active chemical drugs has become a serious concern for both the study supporter (e.g., NIH) and the regulatory agency. 

Third, safety assurance is the responsibility of the FDA, not the manufacturer. This means that the FDA must accumulate a significant amount of proof that something is unsafe before pulling it from the market. In addition, to help professionals, the AHPA has published The Botanical Safety Handbook that summarizes safety data of more than 600 herbs. However, there is no guarantee that any particular manufactured product is safe. An example is a recent recall of PC-SPES supplements by the FDA. The PC-SPES is a combination of eight herbs marketed as a treatment for prostate cancer. It is known to have estrogenic activity, which is presumably how it affects... 

When beginning the development of a TE column procedure, an excellent source of solid-phase extraction (SPE) information may be found in SPE device manufacturers literature (or on their websites). Most manufacturers offer at least 25 years of literature references on their products. Their procedures will often provide useful information about compound types and the SPE chemistries used and solvents for cleanup and elution. The same packing material may be used in the TE column, either the same size (usually 40 - 63 /tm for SPE tubes) or it can be a 5- or 10-/um version of it. Buying the TE packing material from the same company that makes the SPE tubes will allow the solvent information to be used with the on-line work. 

Fats, oils, and lipids are common components of meats, nuts, and dairy products and manufactured goods, such as potato chips, cookies, and chocolate. They are soluble in nonpolar solvents, such as hexane and methylene chloride. The analyte, of course, should also be soluble in the extraction solvent. Typically normal-phase SPE would be used to retain a compound from this extraction solvent. A solid fat may be homogenized in a blender with hexane, filtered or centrifuged, then the solvent would be passed through a normal-phase column for retention of the solute. Another approach is the use of matrix solid-phase dispersion, where the solid would be ground into the silica and C-18 directly, then the analyte eluted directly from the ground mixture with either hexane or methylene chloride. The hexane or methylene chloride extract could then be applied directly to a normal-phase sorbent for separation. Liquid oils may be directly diluted with hexane or methylene chloride and applied to the normal-phase sorbent. Other lipid substances may be handled either as solids or liquids depending on their form. 

The citation of trade names and/or names of manufacturers in this publication is not to be construed as an endorsement or as approval by ACS of the commercial products or services referenced herein nor should the mere reference herein to any drawing, spe cation, chemical process, or other data be regarded as a license or as a conveyance of any right or permission to the holder, reader, or any other person or corporation, to manufacture, reproduce, use, or sell any patent invention or copyrighted work that may in any way be related thereto. Registered names, trademarks, etc, used in this publication, even without specific indication thereof are not to be considered unprotected by law. 

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