Column characterization database

Fig. 10. PC1-PC2 score plot of Cl 8 column characterization database and the analysis of the hydrophilic bases on two similar columns as identified by PCA. For peak assignments and chromatographic conditions see legend of Fig. 9.

As so often nowadays, the answer is in the Internet. Under http //apps.usp. org/app/USPNF/columnsDB.html two column databases can be found. The databases contain data from hundreds of HPLC columns, characterized by means of chromatographic tests such as those described in Section 4.5 [24-27]. The first database is based on the USP test from the National Institute of Standards and Technology (NIST) for the characterization of reversed phases. Unfortunately, this test is not very precise. 

It is worth to note that Haselton et al. make a calibration effort for most of columns of Berry et al. database considering both colunuis that failed in flexural mode and columns characterized by flexure-shear mode, in Fig. 6, an example of the calibration made by Haselton et al. (2008) is shown for the two experimental test specimens provided in Fig. 1. The comparison of the two examples of calibration emphasizes that this component model is very well fitted for columns characterized by flexural behavior and less accurate for flexure-shear-dominated columns. 

A CRO may also allow for the in-house introduction of specialized lipophilic scales by transferring routine measurements. While the octanol-water scale is widely applied, it may be advantageous to utilize alternative scales for specific QSAR models. Solvent systems such as alkane or chloroform and biomimetic stationary phases on HPLC columns have both been advocated. Seydel [65] recently reviewed the suitabihty of various systems to describe partitioning into membranes. Through several examples, he concludes that drug-membrane interaction as it relates to transport, distribution and efficacy cannot be well characterized by partition coefficients in bulk solvents alone, including octanol. However, octanol-water partition coefficients will persist in valuable databases and decades of QSAR studies. 

So far, values of H, S, etc. that characterize column selectivity have been reported for about 200 columns [12-16]. Values for another hundred columns are included in a commercial database (Column Match Rheodyne LLC, Rohnert Park, CA). A procedure for measuring values of H, S, etc. has been reported and shown to give comparable values for the same columns in inter-laboratory testing [17]. Table 2 summarizes average values of H, S, etc. for several different types of columns. Within a given column type, further changes in these column parameters are typical, as illustrated in Table 1 for some type B Cjg columns. 

In Fig. 1, two experimental tests on rectangular RC columns from PEER database by Berry et al. (2004) are shown. The first column, Eig. la, is characterized by flexural-dominated behavior, while the second column. Fig. lb, is characterized by post-yielding interaction between flexure and shear. 

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